Aim Pulmonary infection (PI) is the leading cause of death in patients with primary membranous nephropathy on immunosuppressive therapy. A rating score was thus developed to foresee the risk of PI in such patients. Methods We reviewed the charts of the pertinent patients treated during the past 3 years either with (n = 29) or without PI (n = 304). Clinical and laboratory data, the usage of cyclosporin A (CysA), and occurrence of PI were recorded. Cox regression analysis and receiver operating characteristic (ROC) curve were respectively used to identify the risk factors and assess their clinical relevance. Results The incidence of PI was 8.7% at 82.1 +/- 20.9 days after the initiation of CysA regimen with a male predominance superimposed on smoking. Factors associated with PI were immunoglobulin G titer (hazard ratio = 4.56, 95% confidence interval = 2.31-8.95), plasma CysA concentration (3.71, 1.87-6.18), serum creatinine level (2.57, 1.31-5.82), CD4(+)/CD8(+) ratio (2.36, 1.26-6.06) and plasma albumin content (1.53, 1.05-3.25). These five factors, along with the male gender and smoking status, were granted different ratings after examined by the ROC curve and constituted the anticipating pulmonary infection in primary membranous nephropathy receiving CysA (AIM-7C) score. Accordingly, the respective percent composition of the infection and non-infection group was 0, 11.1%, 72.2%, 16.7% and 91.7%, 8.3%, 0, 0 in the order of low, moderate, high and utmost risk. Furthermore, eight new cases of PI were successfully predicted. Conclusion Our AIM-7C score may therefore help to predict the onset and facilitate the prevention of PI, a potentially life-threatening complication of the immunosuppressive therapy.