Objective To study acute diarrhea status and risk factors of dietary behavior in Shanghai.Methods A stratified multi-stage cluster random household sampling was used in this cross-sectional survey.Results The incidence rate of acute diarrhea among Shanghai residents was 0.68 episodes per person-year.It was 0.75 episodes per person-year for males and 0.62 episodes per person-year for females.It was estimated to be 0.96,0.54,0.71,0.71 and 0.64 episodes per person-year for age groups of 0-7,8-17,18-33,34-59 and ≥60,respectively.24.34% of respondents suspected their illness was due to contaminated food.40.03% of respondents had visited doctor.Single variable and logistic regression analysis showed that odds ratio of acute diarrhea were 1.37(95% confidence interval,1.13-1.67),0.66(95% confidence interval,0.49-0.88) and 0.76(95% confidence interval,0.62-0.94) for the respondents who had the behavior of eating delicatessen,keeping food at low temperature and salty taste.Conclusion Acute diarrhea is a common illness among residents in Shanghai.The incidence of acute diarrhea was slightly higher in males.After the age of eight,the incidence declined,but increased again in adult and then declined above 60.The behavior of eating delicatessen was a risk factor for acute diarrhea.The habit of keeping the food at low temperature and salty taste might be the protective factors for acute diarrhea.