Public health research and interventions often assume that men who have sex with men (MSM) who use the Internet in China have similar characteristics to those in Western countries, though with little empirical evidence. This study aimed to describe and examine the sociodemographic and basic sexual behavioral characteristics of an online sample of MSM in Guangdong, China. In 2010, a total of 1100 MSM were recruited from an lesbian, gay, bisexual, and transgender (LGBT)-oriented website and were asked about their sociodemographic and sexual behavior characteristics. The majority of the participants (77.9%) self-identified as homosexual, and the mean age was 30.0 years (SD = 6.7). About 80% of the participants had attained a college degree and only 4.8% were unemployed. About 60% had a monthly salary of more than CNY 3000 (476 USD), and more than 10% were married. The majority (71.7%) had used condoms in the last anal sex. Nearly half of the participants have never been tested for HIV or other sexually transmitted infections (STIs) (47.3% and 47.7%, respectively). More than 80% were willing to be contacted by researchers after the survey. Findings indicate that the sociodemographic characteristics of Chinese MSM who use the Internet are relatively similar to those in the Western countries. However, Chinese MSM are less likely to self-identify as homosexual and be tested for HIV and other STIs than Western MSM. On a positive note, Chinese MSM would be likely to engage in e-technology research showing potential feasibility of an online HIV/STI intervention.