Abstract: Biological characteristics, life cycle and epidemic law of Micromelalopha troglodyte in Shanghai were studied for the first time. There are 5 generations per year, specially up to 6 generations. After the first generation, there is a severe generation overlap phenomenon. Epidemic is closely related to climate and environment:there is some prominent positive correlation among its population and original pest density, daily average temperature, rainfall; daily mean humidity. This insect occurred when the daily average temperature was over 15℃, and prevailed when the daily average temperature was 25~30℃, daily mean humidity was 65%~ 85%, daily mean rainfall was 50~150 mm. On this base, a short-term forecast model was built:Y=-- 101. 909--0. 091xl +0. 155x2 -t-0. 338x3 +0. 659x4 +-0. 539x5, R=0. 739. After being tested, the model has a high accuracy and can be used to forecast in Shanghai.