Abstract: Pneumocystis jiroveci pneumonia (PJP), previously named pneumocystis carinii pneumonia, one of the fungoid and opportunistic infections in lungs, is commonly found in dysfunction of immunity, including Acquired Immunodeficiency Syndrome (AIDS), organ transplantation, long-term treatment with immunosuppressant or corticosteroids, malignant tumor and suffering from chemotherapy, and so on. PJP has a characteristic that there is a discrepancy with a mild sign and a serious symptom of low-grade fever, nonproductive cough, and progressive dyspnea. If necessary diagnosis and treatment could not be implemented on time, its mortality rate would be increasingly high, with a sharp development. The typical image of PJP is bilateral, diffused, and symmetrical ground-glass opacity around the hilus pulmonis. The image of PJP can be divided into five types, including ground-glass opacities dominated, lung cysts dominated, consolidation dominated, interstitial lesions dominated, and mixed lesions pattern. If a patient with AIDS appears spontaneous pneumothorax, the most possible cause is the infection of pneumocystis. The early identification and diagnosis with typical image for PJP, and the following specific treatment, play an important role in prognosis of patients.

Key words: Pneumonia, Pneumocystis, Acquired Immunodeficiency Syndrome, Tomography, X-Ray Computed