Abstract: Great variation in structure/intensity of tropical cyclone(TC) usually occurs around the period of TC landfalling. Much important processes would be its interaction with mid-latitude circulation systems (MLCS).Such interaction would affects not only TC but also the weather in certain ares in mid-latitude. TC vertical wind shear appears tilt influenced by midlatitude circulation systems,and part of warm air of TC will be dispersive,the surface pressure will rise and the TC intensity will get weaked. There will be some supper cloud cluster and eyewall vortex within TC influenced by trough in westerlies (TW),and the TC precipitation will be amplified by 30% abruptly if the TW intensity increases. The TC unusual movements are closely related to adjustment of MLCS and the TC asymmetric structure affected by MLCS. A great deal of water vapor enters the mid-latitude region along with TC polarward drifting,carrying mass energy from TC to the cyclonic shear in MLCS,which is favorable to the enhancement of the MLCS and appearance of heavy rain. On the other hand,TC could cut off the water vapor transportation channel from low to mid-latitude. About 95% of TCs of South China Sea have remarkable effect on MeiYu weakening and about 86% of TCs can interrupt or cease the MeiYu rainfall. This paper discusses the interaction between TC and MLCS as well as the relevant issues concerned.