Abstract: Based on forecasting criteria of tropical cyclone track types: break(right/left turning) and steady tracks in the South China Sea and its nearby region, appling fuzzy mathematics principles,a fuzzy probability forecasting method for tropical cyclone tracks' change type was given in this paper. The method can be used to forecast whether a tropical cyclone's track will change or keep stable in 48 hours lead-time.Its forecasting output is in a fuzzy probability.Operational experiments with the method show that its forecasting output is objective, quantitative and definite,its running system is easy to operate,and the forecasting accuracy is good.Especially, when fuzzy probability is greater than 70%,errors of moving direction and 48 hours forecast are obviously smaller than those of subjective forecasts made by main weather stations. It is worthful of giving a reference to forecasting.