Abstract: Objective To understand the incidence trend of acute hepatitis B and related risk factors in Tianjin. Methods The incidence data of acute hepatitis B in Tianjin from 2005 to 2013 were collected from national disease reporting information system to conduct descriptive epidemiological analysis in order to understand the cases' population, time and place distributions. And questionnaire survey was conducted among acute hepatitis B cases in 2013 to collect the information about their demographic characteristics, risk factors and vaccination histories. Results A total of 3 298 cases of acute hepatitis B, including 4 deaths, were reported in Tianjin from 2005 to 2013, the incidence was 3.07/lakh (2=567.265, P=0.000), and the predicted incidence would be 1.11/lakh in 2014. The incidence in age group 20 years was 1.07/lakh, lower than that in age group 20 years (3.53/lakh) (2=323.378, P=0.000). The incidence in males (4.44/lakh) was higher than that in females (1.61/lakh) (2=701.001, P=0.000). Related risk factor analysis for 164 cases indicated that 33 (20.12%) had close contacts with HBsAg positive persons and 21 (12.80%) had dental surgery histories in private dental clinics, and the HepB vaccination rate was only 5.49% among these cases (9/164). Conclusion The incidence of acute hepatitis B is low in Tianjin and HepB vaccination has protection in people covered. Close contact with HBsAg positive person, dental surgery in private clinic and low HepB vaccination rate are the risk factors for acute infection with hepatitis B virus.