Membrane bioreactor (MBR) is a new waste water treatment technique, in which through efficient interception effect of the membrane, sludge concentration in the reactor can be kept very high, thereby sludge load is reduced and the system processing efficiency is enhanced. MBR is applied to treat production and life waste water in gas treatment plant, more than 90% of CODcr, BOD5, oil, ammonia and nitrogen can be effectively removed from waste water, the treated water is clear, limpid and odorless and do not produce secondary pollution.