Abstract: Objective To understand the risk factors and disease burden of acute diarrhea among the floating population in Hangzhou. Methods A retrospective investigation on acute diarrhea incidence was conducted in floating population in 3 districts in Hangzhou in March, June, September and December, 2013. Results A total of 1813 subjects were included in the study. The four-week incidence was 4.03% and the incidence density was 0.54 time/person-year. The four-week incidence in floating population from rural area (4.36%) was higher than that in those from urban area (0.33%) (2=4.53, P=0.033). The results of logistic regression analysis indicated that original living area, age and educational level were related factors affecting the incidence of acute diarrhea. Among 73 diarrhea cases, 21 (28.76%) once sought medical care. The average work time loss was 0.4 day and average medical care cost was 58.22 yuan. Conclusion The incidence of acute diarrhea were high in floating population from rural area and in children aged 10 years, to which close attention should be paid.