Background. Mobile Rural Workers have been widely concern as potential source ofnew HIV infections in China, due to the nature of the mobility and magnitude of thepopulation.Objective. The study aimed at assessing disparities between mobile rural workers andlocal residents in HIV-related vulnerability by exploring important contextual factorscontributing to the disparities.Method. A sample of 134 mobile rural workers and 127 local residents weresystematically recruited into a cross-sectional study. All 261 participants responded toa close-ended questionnaire and 24 attended a Focus Group Discussion. Informationon HIV-related knowledge, attitude and perception, risk behaviors, mobility status aswell as socio-economic status were collected and analyzed.Result. Adjusted for sex, age and education, mobile rural workers were more likely tohave lower income (OR =3.06, 95% CI: 1.31-7.18), no medical insurance (OR =6.58,95% CI: 2.95-14.71), less social support (OR =2.13, 95% CI: 1.04-4.33), and poorknowledge on HIV (OR = 2.5, 95% CI: 1.05-5.99), compared to local residents.However, mobile rural workers were less likely to have multi-partners than their localcounterparts (OR =0.3, 95% CI: 0.11-0.84). Among the mobile rural labors, femaleswere more likely to be less paid (OR=7.69, 95% CI: 2.17-25), and less likely to getaccess to condom (OR=4.25, 95% CI: 1.64–11.00) compare to males. Differences inincome, social support and condom access between mobile rural workers and localresidents were much larger in female group. No female mobile worker reported multipartnershipin the study.Conclusion. Compared to local residents in Beijing, mobile rural workers were morevulnerable to HIV infection in terms of economic constraints, access to medicalservices and insurance, social support and HIV-related information and knowledge.Gender disparity predisposed woman mobile workers for higher level of vulnerability.Marginalization of mobile rural workers poses potential threat to HIV/AIDSprevention, and should be averted by addressing inequity during the process ofeconomic development and socio-cultural transition at host communities.