To understand the current situation and characteristics of commercial sexual behavior among old male clients in Guangxi, and to explore the associated risk factors of HIV infection. The areas in Guangxi where more old male HIV cases were reported followed by survey on those male clients who were over 60 years of age, were selected. A total of 5 ml blood sample was collected to test antibodies of HIV and syphilis. Risk factors were calculated by the multivariate logistic analysis method. A total of 1 236 questionnaires were completed in the survey. 65.61% of the old male clients were from low-grade venues with 53.64% of them never using a condom when engaging in commercial sex behavior. 47.33% of them patronized sex workers for around 10 years. 53.32% of them patronized prostitutes not less than 2 times in the last 30 days. Thirty subjects were HIV positive (2.43%) and 40 were syphilis positive (3.24%). Factor as 'having fixed partners' (OR = 0.302, 95% CI:0.140-0.650) appeared protective for the old male clients of HIV infection, with a history of patronizing sex workers from 1 to 5 years (OR = 2.552, 95% CI: 1.086-5.998). Frequency of patronizing sex workers not less than 4 times in the last 30 days (OR = 3.002, 95%CI:1.047-8.607) seemed the high risk factor of HIV infection. Older-aged male clients showed high HIV and syphilis infection rates in Guangxi, and most of them were using the low-grade venues. Commercial sexual behaviors in the areas would include early and, frequent exposure, but with poor protections. High risk factors of HIV infection might relate to "no fixed sexual partners" and "frequently commercial sexual behavior".