Objective:To understand the infection rate of HCV in drug users(DUs) and figure out the risk factors related to HCV infection,in order to provide basis for prevention and control in the particular targeted population. Methods:DUs,who were arrested from April to June,had been randomly sampled at 7 treatment centers and camps from 2005 to 2008. And a total number of sampled DUs was 2 811. Blood was collected for HCV antibody testing by ELISA assay after face to face interview. The data were checked by EpiData 3.1 software before the establishment of databank,and analysised by SPSS 11.5. Results:Among the 2 811 DUs,957 of them were HCV positive(34.0%),and the positive rate in male and female were 35.1% and 29.2%,respectively. Men showed higher positive rate than women( -字2=6.32,P < 0.05). The age range of participating was 18~74 years old. The positive rates were different in various groups and the highest rate was found in the 30~39 years old group. Significant inter-group difference was found(-字2=65.31,P < 0.05),but no significant difference was figured out among DUs between Jiangsu province and others,or DUs in various marital status groups. Drug used by injection,sexual behavior for money or drug,and sexual behavior without condom used were high risk factors for HCV infection. Conclusion:The positive rate is much higher in DUs than normal population,which suggests that the special group has risk factors for HCV epidemiology,and should pay more attention in prevention and control of HCV infection. More targeted integrated measures to DUs on health education and behavioral intervention should be performed for prevention and control.