To understand the HIV epidemic and its correlation among the community-based drug users in Dongguan, Guangdong province. In 2008, 13 drug users were identified as seeds in Dongguan. Respondent driven sampling was applied to recruit community-based drug users. A structured questionnaire was used for a face to face interview. Intravenous blood samples were collected for the measurement of HIV, HCV and syphilis antibodies. RDS analysis tool (RDSAT) was applied for adjusting the estimates and bivariate analysis. A total of 303 drug users were recruited within 15 weeks and 300 blood samples were collected. After RDSAT adjustment, the prevalence rates of HIV, HCV and syphilis were 14.7% (95%CI: 6.1% - 25.4%), 63.2% (95%CI: 55.7% - 71.7%), and 4.7% (95%CI: 1.8% - 8.2%) respectively. The HIV prevalence rates among those who were HCV seropositive, migration, younger than 26 years at their first drug use, and ever shared needles or syringes were 22.9% (95%CI: 10.8% - 37.0%), 26.9% (95% CI: 11.4% - 44.9%), 19.9% (95%CI: 8.3% - 35.7%), and 29.1% (95%CI: 12.3% - 45.1%) respectively. The proportions of the drug users who were enrolled at methadone maintenance treatment (MMT) of local residency, migration were 20.9% (95%CI: 4.1% - 44.6%), 2.3% (95%CI: 0.0% - 7.0%) respectively. The HIV epidemic among the community-based drug users in Dongguan is serious. Drug users who are HCV seropositive, migration, younger than 26 years at their first drug use, and ever shared needles or syringes are more likely to be HIV seropositive.