The clinical data of 185 patients with rheumatic heart disease (RHD) proved by pathological biopsies were recorded before operations, and analysed using the stepwise regression analysis of multi-factors (SRAM). A mathematical formula to judge the activities of rheumatism in RHD was applied. The multi-factors were put in order according to their importance in effect: progressive reduction of cardiac function (age less than 30), sustained atrial fibrillation, recent changes in heart murmur or onset of a new murmur, paroxysmal atrial fibrillation, speed-up of erythrocyte sedimentation rate and acute pulmonary edema (age less than 30). 310 cases of RHD were tested and verified by this formula, 85.5% of them were diagnosed correctly in comparison with Aschoff's bodies observed by pathological biopsies in left cardiac atrial appendages. All cases were operated and confirmed by pathological examination. The presence of Aschoff's bodies in atrial appendages was considered the index of active rheumatism pathologically.