Abstract: Based on 1958—1997 monthly mean data of 500 hPa height and 1000 hPa wind, temperature, sea surface temperature and outgoing long-wave radiation, the features in the former autumn-winter season for anomalous frequency of tropical cyclone affecting East China are discussed with the composition analysis method. It is shown that these different features relate to the anomalous winter monsoon. Therefore, winter monsoon has influence on the frequency of tropical cyclones affecting East China. Finally, a diagnostic conceptual model is constructed. The prediction experiments are conducted and the results show that the conceptual model has reference value to forecasting the anomalous frequency of tropical cyclones.