The efficiency of treatment on food wastewater was studied by observing the process of anoxic/aerobic membrane bioreactor(A/O MBR),and the effect of whole process was investigated by adding powdered activated carbon(PAC) into the anoxic tank in the later stage of experiment.The following results were obtained: A/O MBR added with PAC has good performance in purifying food wastewater;the average COD removal efficiency is 96%;the average NH3N removal efficiency is 91%,and the turbidity removal efficiency is almost 100%.It is also proved that A/O MBR added with PAC is better than that without PAC in removing NH3-N and COD,and can reduce membrane pollution to a certain degree.