Objective To explore the relationship between eating out and diarrhea in Chinese residents.Methods Based on the data of Epidemiological factors of key disease in 8 cities of China from the National Health and Family Planning Dynamic Monitoring project in 2017， the relationship between eating out and diarrhea was analyzed by SPSS.Results A total of 14 000 subjects were included in the analysis， including 7 172 （51.2%） males， with an average age of （34.6±10.1） years old. 2 419 patients had diarrhea with an incidence of 17.5%. The results of univariate analysis showed that gender， age， ethnicity， educational background， type of drinking water， whether they often ate cold dishes， whether they separated raw and cooked kitchen knives and chopping boards， and the type of meals at different times were statistically correlated with diarrhea， and P value were all lower than 0.05. After adjusting for 9 confounders， such as gender， age， ethnicity， education level and marital status， Logistic regression analysis showed that the OR （95%CI） of those who ate in the canteen was 1.45 （1.19~1.77） compared with those who ate at home. The adjusted OR （95%CI） of eating out for one meal， two meals and three meals were 1.28 （1.14~1.44）， 1.58 （1.25~1.94） and 2.28 （1.58-3.29）， respectively.Conclusion Eating out， especially take-out/street stalls/fast food restaurants， increased the risk of diarrhea. Residents should be encouraged to reduce eating out.