ObjectiveTo understand the therapeutic effect of clindamycin combined with compound sulfamethoxazole tablets on pneumocystis pneumonia(PCP) associated with acquired immunodeficiency syndrome (AIDS). Methods97 AIDS patients with PCP in a hospital from January 2014 to March 2015 were randomly divided into control group (n=49, received compound sulfamethoxazole ) and trial group(n=48, received clindamycin on the basis of compound sulfamethoxazole ) , levels of partial pressure of oxygen in arterial blood (PaO2), arterial blood oxygen saturation（SaO2）, serum albumin(ALB), and lactic dehydrogenase (LDH）in two groups of patients before and after treatment were recorded. ResultsLevels of PaO2, SaO2, ALB, and LDH between two groups of patients before treatment was not significantly different(all P>0.05). After treatment, PaO2 in control group and trial group were（73.01±4.62）mmHg and（84.92±5.34）mmHg respectively，SaO2  were （75.81±4.28）% and（90.86±5.94）% respectively，ALB were (32.62±4.41)g/L and（43.95±5.03）g/L respectively，LDH were（416.53±30.77）U/L and（331.58±20.86）U/L respectively，levels of PaO2 and  SaO2 in trial  group were both higher than control group , difference in ALB and LDH between two groups of patients after treatment were both statistically significant( both P<0.05). The total effective rate of trial group was 89.58% (n=43), which was higher than 69.39%(n=34) in control group （χ2 =6.04，P=0.014）. ConclusionClindamycin combined with compound sulfamethoxazole tablets has good therapeutic effect on AIDS and PCP, which is worthy of clinical popularization and application.