Abstract: The tropical cyclones forecasting operational system in Liaoning province and its forecasting results in the year of 2005 were introduced based on MM5 in this paper.The background field and the boundary were created by T213L31 product.The initial field assimilated sounding data,the surface observations and satellite retrieval data,and Bogus TC were also set in the initial field.The system ran twice every day automatically.The post processing products were programmed the graph system of GrADs in order to display charts,and it was showed on meso-scale numerical forecasting web pages of Shenyang Regional Meteorological Center Local Area Network.The tropical cyclone forecast in the flood season in 2005 indicated that the system was suitable to the tropic cyclone route forecast and rainstorm forecast.