To evaluate the effect of the social support on adherence of highly active antiretroviral therapy (HAART) of people living with human immunodeficiency virus/acquired immune deficiency syndrome (PLWHA). Participants of PLWHA at Beijing, China were intervened by 1-year social support program intervention. Difference of social support scale and medication adherence scale before and after the intervention were evaluated. Our results showed that there were statistically significant difference for total score and subjective score, medication adherence between before and after intervention (t = −3.62, −2.81, 5.75, P < .05), and there were statistically significant correlation between the difference of total social support score and that of social support utilization score, and the difference of medication adherence score (r = 0.14, 0.12, all P < .05). Multifactor linear regression showed that the medication adherence score was influenced by the insurance status, the residential status, and the difference in the social support utilization score (β = −0.14, 0.17, 0.16, all P < .05). Social support and care-giving can exert some influence and facilitate PLWHAs adherence of HAART.