Based on the analysis of 37944 hospitalized breath disease case data of five big hospitals in Fuzhou and weather data at the same time, the relation between characteristics of breathing diseases and weather variation is summed up. By means of the optimized subset method, four forecast equations are established for four seasons. The results show that breathing diseases have obvious seasonal change; generally, July and March are two paroxysmal periods of breathing diseases; in winter, cold air and sudden weather changes are inducements of breathing disease increase, and in summer, high temperature and low atmospheric pressure are inducements of breathing disease increase.