The epidemics of sexually transmitted infections (STIs) have spread among older adults in the world, including China. This study addresses the deficiency of studies about the multiple contextual influences on condom use among mid-age female sex workers (FSWs) over 35 years old. A combination of an egocentric network design and multilevel modeling was used to investigate factors of condom use over mid-age FSWs (egos) particular relationships with sexual partners (alters). Of the 1245 mid-age FSWs interviewed, 73% (907) reported having at least one sexual partner who would provide social support to egos. This generated a total of 1300 ego-alter sex ties in egos' support networks. Condoms were consistently used among one-third of sex ties. At the ego level, condoms were more likely to be used consistently if egos received a middle school education or above, had stronger perceived behavioral control for condom use, or consistently used condoms with other sex clients who were not in their support networks. At the alter level, condoms were not consistently used over spousal ties compared to other ties. Condoms were less likely to be used among alters whom ego trusted and provided emotional support. Cross-level factors (egos' attitudes toward condom use and emotional support from alters) documented a significant positive interaction on consistent condom use. Given the low frequency of condom use, future interventions should focus on mid-age FSWs and their partners within and beyond their support networks.