Abstract: According to the records of fog in the Capital Airport during the period of 1958 to 1994, the statistical climate characteristics of fog occurring in Beijing area are analyzed. The observing data and the physical fields before fog are calculated and a nalyzed, and a method for short-range forecasting fog is provided. The method is verified during July 1-Nov.30, 1998 with high accurate rate of forecasting. The route of step-predicting guideline on fog is suggested.