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