Objective: To identify the status and determinants of sharing personal HIV information with sexual partners among men who have sex with men (MSM) meeting their casual sexual partners on the internet. Methods: A cross-sectional study was conducted in five cities (Hangzhou, Ningbo, Wenzhou, Taizhou and Shaoxing) in Zhejiang province. The recruitment was enrolled by MSM social organization and in voluntary counseling and testing clinics, with a sample size of 793. A self-designed network questionnaire collected essential characteristics, HIV knowledge, sexual behavior, and sharing personal HIV status. SPSS 20.0 software was used for statistical analysis. Results: Among 767 MSM enrolled 302 MSM who reported finding casual sexual partners on the internet were enrolled in the analysis. MSM reported finding casual partners on the internet only, finding sexual partners online and in places were 62.6% (189/302) and 37.4% (113/302), respectively. Among those reporting web-based sexual behavior in the last six months, 54.6% (165/302) informed their partners of their HIV status, 49.2% (146/297) inquired about HIV status, and 42.9% (82/191) knew HIV status before sex intercourse, 75.8% (113/149) reported consistent condom use with HIV negative partners. The multivariable logistic regression analysis showed that related factors of inconsistent inquired HIV status of partners included 25-34 years old (aOR=2.17, 95%CI: 1.20-3.91), >2 partners on the internet in the last six months (aOR=2.13, 95%CI: 1.27-3.57), low-risk perception of HIV infection with online partners (aOR=1.96, 95%CI:1.14-3.35), numbers of HIV testing >1 times (aOR=0.38, 95%CI: 0.22-0.66). Conclusions: The willingness to know the HIV status of partners among MSM who met sexual partners on the internet was high but with a low rate of knowing their sex partner's HIV status in Zhejiang province. However, the successful implementation proportion was low. Therefore, it is necessary to pay attention to people who are elderly, with less conscience about the risk of the sex partners on the internet, have more sex partners, and have received few HIV tests. In addition, peer education was needed to promote related intervention programs.