The effect of different atmosphere conditions,including CO2,O2 and N2,on the quality of chilled pork was studied in this paper.Total 6 combinations were selected to study the changes of total viable count(TVC),total volatile basic nitrogen(TVB-N) value,thio-barbituric acid(TBA) value,and sensory score of chilled pork during 7-day storage with modified atmosphere package(MAP).Results showed that the quality of chilled pork within different groups changes significantly.It showed that under 40% CO2,40% O2 and 20% N2,the TVC of chilled pork were under the spoilage level,and the values of TVB-N and TBA were all within acceptable range.Meanwhile,the sensory evaluation was better than that of other MAP conditions.The conclusion is the combination of 40% CO2,40% O2 and 20% N2 was the best.It can be used as the theoretical reference of MAP optimization for chilled pork storage.