Abstract: For the annual frequency of tropical cyclones affecting the Hainan province, the methods of accumulative anomaly, smoothing T-test and Cramer's Mam-Kendall are used to conduct tendency analysis and detection for abrupt changes. Then, predictions are made of the tendency of the annual frequency for TC for the next 10 years employing the orthogonal treatment of ambiguity generalized functions. As is shown in the result, the 1946 is the abrupt change point at which a period of few typhoons ends and a fresh period of more typhoons legions. It is predicted that Hainan is within a period of fewer typhoons by 2004 but may, from 2005 on, step into a period in which the typhoon become active.