The typhoon Jelawat landed at Xiangshan, Zhejiang and weakened speedily after landing. Its ratio of intensity attenuation was in large excess of the average and the affection on Hang Jia Hu region was not big. The main reason is that typhoon Jelawat was far away from ITCZ and couldn't gain energy. During its landing, the mainland high was very strong, the weather was drought, the atmosphere was dry. Due to its friction with the mountain terrain, the energy was given out. After it landed, the relative divergence of the upper layer 500hPa and the lower 850hPa was negative and the wind speed decreased. In addition, the effect of the landed typhoons on the 10th day or later on Jiaxing city is small according to the data of statistics. The results may serve as reference for prediction of landing typhoon.