Abstract: Objective To understand the change in bacterial diarrhea pathogen spectrum in Tongzhou district of Beijing during 2011-2015 and provide scientific evidence for the prevention and treatment of diarrhea.Methods Stool samples were collected from diarrhea patients in sentinel hospital for the detection of related bacterial pathogens.The results were analyzed by using software SPSS 17.0.Results A total of 3 270 stool samples were collected from 2011 to 2015,and the overall positive rate of bacterial pathogens was 37.71%.In addition to other bacteria,the proportion of Vibrio parahaemolyticus was highest (23.40%) in 2011,while the proportions of Escherichia coli were highest (13.94%,19.40%,49.13% and 38.05%) during 2012-2015.The annual positive rate peaked during June-September.The positive rate was low in age group 10 years,and the positive rates were all 30% in other age groups.The differences in pathogen constituent among different age groups was significant (P=0.001).Conclusion Compared with the previous years,bacterial diarrhea pathogen spectrum changed in 2012.The main pathogen of diarrhea had changed from V.parahaemolyticus to E.coli.