The men who have sex with men (MSM) population in China has experienced a recent increase in HIV incidence. Due to the dual stigma and discrimination towards homosexuality and HIV infection, most MSM living with HIV/AIDS are hard to reach by offline intervention initiatives. We recruited HIV-positive MSM participants in Chengdu, China and assessed whether they disclosed their HIV status to partners, motivated a partner to receive testing, used condoms consistently, or initiated antiretroviral therapy. Participants were quasi-randomized to either the intervention or control arm. The intervention group was given instructions for an online program with four modules: an information exchange website, a bulletin board system, individualized online counseling with trained peer educators, and an animation game. All participants were re-assessed at 6 months. The study enrolled 202 HIV-positive MSM. The intervention group had significant increases in disclosing their HIV status to their partners (76.0% vs 61.2%, P=0.0388) and motivating partners to accept HIV testing (42.3% vs 25.5%, P=0.0156) compared with the control group, but there were no between-group differences in receiving early treatment or using condoms consistently. We found that a web-based intervention targeting HIV-positive MSM was an effective tool in increasing the uptake of HIV testing within this high-risk population.