Abstract: Objective The investigation was conduced to understand HBsAg infection among senior high school graduates and provide a scientific basis for constituting strategies against Hepatitis B to protect students' health. Methods Serum HBsAg and ALT Were detected by ELISA(Enzyme—Linked ImmunosorbentAssay)among 201 483 senior high school graduates from 1998 to 2005 in the city of Taizhou．And the results were statistically analyzed．Results The mean positive rate of HBsAg was 11.28％ among senior higll school graduates，higher than the average positive rate in general population. It was found that positive rate of HBsAg was highest in 1998 (13.81％)，and decreased year by year thereafter，with the rate being lowest in 2005 (9.66％).The rate was significantly higher among boys than among girls(pp<0.Ol)with the rate being higher in counties (13.33％)than in the city(11.36％)and lowest in districts (8.44％)．Conclusion It is seen that HBsAg infection rate among high school students takes on a trend of decreasing year by year Strengthening inoculation of Hepatitis B vaccine among newborns and SUSCeptibin population to improve immunization coverage rate and population immunization level is an effective approach to the reduction of HBV infection