ObjectiveTo investigate the clinical characteristics，diagnosis and therapeutic prognosis of Pneumocystis pneumonia（PCP）in patients with acquired immunodeficiency syndrome (AIDS).MethodsAIDS  patients with PCP were searched through computer medical record information system， clinical data were analyzed retrospectively, patients were divided into respiratory failure group (n=11) and nonrespiratory failure group (n=12)，partial pressure of oxygen in arterial blood（PaO2）， degree of blood oxygen saturation(SaO2),CD4+T lymphocyte, and lactate dehydrogenase（LDH）between two groups were compared.Results23 patients generally had the symptoms of weight loss，oral leukoplakia，shortness of breath, dyspnea， fever， cough，and expectoration. PaO2 value in 23 patients was (78.65±30.85）mmHg， partial pressure of carbon dioxide（PaCO2）was (24.42±5.60) mmHg，pH value was（7.43±0.79），SaO2 was （91.16±9.55）%；SaO2 and PaO2 in  respiratory failure group was lower than  nonrespiratory failure group, the difference was significant (both P＜0.05).Lung computed tomography (CT) scans showed bilateral pulmonary groundglasslike change. 21 patients used compound sulfamethoxazole tablets, 1 patient used compound sulfamethoxazole tablets plus clindamycin，1 patient used only clindamycin，17 patients used glucocorticoid in addition to compound sulfamethoxazole；after treatment,20 patients improved，2 died，and 1 gave up treatment.ConclusionSubacute progressive dyspnea, fever, dry cough,and lung groundglasslike shadow are common symptoms of PCP in AIDS patients,  compound sulfamethoxazole or compound sulfamethoxazole with clindamycin can be used for treatment, glucocorticoid  can obviously alleviate the symptoms of patients.