Detention centers - mainly for administrative detention, but some may detain over a year in extreme cases. Most are under 3 months.
Re-education camps - run by public security for 1-3 years, usually 1 year max, but most have been abolished.
Drug rehab centers - won't elaborate as I'm not familiar.
Jails - where criminals stay before sentencing. In poorer areas, detention centers double as jails. Key difference is jails hold death row inmates (usually in fixed cells).
Longest jail term I know is 6 years (death penalty case with repeated appeals and supplementary investigation). Normal inmates spend under 1 year, maybe 1.5 years until second trial before going to prison.
Finally there are the prisons. These include:
Regular male prisons - most common.
Admission training team - newcomer bootcamp for 1-2 months, less common now.
Female prisons - some people's favorite.
Juvenile prisons aka juvenile detention centers.
Maximum security prisons - for 15 years to life sentences.
Note that no matter the term, including life or death with reprieve, max serving is 20 years.
Foreign prisoner prisons - some adapted regular cell blocks.
Most famous is Qincheng Prison, the Justice Ministry's "heavenly prison". Only ministerial level officials can enter. Directly administered by the Public Security Ministry (most prisons are under Justice Ministry).
Another online sensation is Tilanqiao Prison - besides the accountant classes, a prisoner there designed the Changjiang 750 tractor in the last century.
But some super secret jails may be even higher security - can't divulge more about those.
Inmate levels aren't "boss, number two" etc. Official levels are:
Level 1 and 2 privileges, general population, strict management, solitary confinement - denoted by green, light blue, blue, orange and red badges.
Then different inmate jobs like cell leader, duty inspector etc. Titles vary locally.
Food - focusing on prisons here as quality varies drastically for other facilities. Inmate meals have a state subsidy plus prison revenue contribution.
Nowadays, vegetable dish and soup provided as minimum regardless of prison. Weekend and holiday meals are better. Some prisons have 4 meals (2 morning, some have 3). Food quality is decent, no pre-cooked food, kitchen prepares meals then distributes to cell blocks.
Mass cafeteria meals (as seen on TV) are rare now.
As a reference, in one coastal province in 2010, the per capita food standard was 320 RMB per month. The food was quite good with meat and vegetables. Generally, northern prisons have worse food than southern ones. Poorer areas have lower standards, better economies mean higher prison revenue and better food. Inmates can also buy snacks, noodles, side dishes etc at prison convenience stores for normal prices (jails mark up more).
Also, most prisons banned smoking around 2015, with local variance for jails.
Moving on to housing - standard cells fit 10, with 5 bunk beds, TV and toilet. Rarely large barrack style now. Notably there's only cold water year-round, no hot showers (some inmates can shower with hot water, either through connections or if the prison provides hot water).
Rooms inspected for military-style standards and marked.
Set TV times (prison education channel) with all channels open on weekends and holidays (normally only 3-5 channels). Occasional sports time with guards, but not common. Libraries also quite for show - well behaved inmates can apply to borrow books (with guard approval).
Standard 8-hour workday (no OT, prisons report to Justice Ministry). Production quotas linked to economic output - failure can lead to solitary or other punishment like loss of points, but no direct violence.
Mostly light industry now - used to have mining, cement, oil, agriculture. Now lots of shoes, garments, tents, umbrellas. Outside companies place orders, including the famous TianTang umbrellas partly made in prisons.
Don't say treadle sewing machines anymore - say flatbed computerized sewing machines, specialty machines, overlock machines.
Daily output recorded per inmate. Salary calculated normally (only get 5-10% each month, varies locally), rest goes towards sentence reduction at 1 day per point.
Inmates with skills are in demand - clothing, electrical, painting, landscaping, IT, machinery maintenance. Learning a skill pays off anywhere.
Military experience also valued - may train new inmates. Higher education also useful - illiterate inmates taught by more educated ones.
Connections help of course, but skills and willingness to learn pay off.
Resisting change has countless consequences, not just violence. As mentioned before, privilege levels like Level 1 or 2 can determine what you can buy monthly. Resisting could get you knocked to solitary, severely limiting purchases.
Prison hierarchy is (prison-warden and party secretary, typically deputy bureau chief level, joint top leaders, sometimes party secretary has more power, some prisons have governor instead of warden, key prisons may have deputy bureau chief governor).
Departments - Political, Production, Education, Internal Investigations, Medical etc, around 10, with important heads dual-hatting as deputy wardens.
Cell blocks - block chief often dual hats as deputy warden.
Then housing units of 100-200 inmates per unit, 3-6 units per block.
Two special units for logistics and new inmate training.
Provincial level also has dedicated prison hospitals - mostly medical student interns...
Some other interesting points:
Contraband like cigarettes, alcohol, MP3 players, knives, even mirrors and most books confiscated.
Some inmates can obtain them or deal them at high prices - prison black market.
Alcohol especially hard to obtain, but homemade liquor exists - purified water + fruit, or sugar + pears (sold at prison stores).
Canteen buys limited monthly - special finger-wrap toothbrushes, pens etc. Purchase amount and items allowed depends on level. Solitary only 60 RMB, Level 1 maybe 800 RMB max (very rare).
Separate summer/winter uniforms. Inmates alter them for identification.
Theft exists but seriously punished and socially scorned. Most inmates can afford canteen purchases through wages.
Some inmates wash dishes, laundry, massages or make beds for goods - called "horses". Unit leaders have private horses, some just do laundry.
Earlier questions asked about prison violence and social hierarchy. In summary:
More violence in jails - offenders like rapists may be assaulted (depends on local or outside inmates, wealth). Wealth and connections mean you can abuse others.
Prisons are more civilized. Long timers especially avoid trouble for sentence reduction. Short timers often more aggressive (under 3 years hard to get reduction). Crimes don't affect status much. Trouble is rare with cold violence deterrence - solitary, level drops, loss of points over direct beatings (unavailable on cameras).
But resisting reform brings consequences, with monitoring blind spots.
Whether gay inmates exist - long termers may become deviant but don't dare show it.
Can write monthly, monitored. Monthly half hour visit through glass, recorded and listened to. Good behavior or connections may allow paid emotional calls.
Most conjugal rooms banned now. Some prisons have children's homes for inmates' kids lacking care.
No direct violence but endless pretexts for "resisting reform". E.g. guards drawing a circle and you can't leave for hours. Using toilet or anything requires reporting. Complete military control.
Leaving housing unprompted can be deemed escape attempt - armed patrols authorized to shoot.
prison cell
In my view, while Chinese prisons maintain order, the environment breeds hopelessness instead of rehabilitation. More vocational training and counseling should be provided to help inmates re-enter society. Guards could also receive training in positive reinforcement instead of solely punitive measures. The goal should be reducing recidivism rates.