The utility model discloses an automatic defogging control system of cooling tower, it includes data acquisition module, the data?analysis?module who is connected with data acquisition module and the control module who is connected with data?analysis?module, data acquisition module be used for gathering humiture parameter, the environment of cooling tower air outlet the humiture parameter, advance the dry and cold air amount of wind parameter of tower and advance the clammy air amount of wind parameter of tower, data?analysis?module is used for the parameter data who receives data acquisition module to have or not rain and fog to judge or the operating mode tentative calculation, what control module was used for receiving data?analysis?module's signal and controlled dry and cold air, clammy air advances opening and close of the tower amount of wind and first pipeline, second pipeline. The utility model discloses an automatic defogging control system of cooling tower, root the tower mouth humiture and the environment humiture of gathering, automatic control is dry and cold, clammy air advance the tower amount of wind, reduced artifical intensity of labour, realized the no -man control defogging, improved separation efficiency greatly.