The invention relates to an automatic dehumidifying method which is implemented on an automatic-dehumidifying three-layer glass window. The automatic-dehumidifying three-layer glass window comprises awindow body, a water drop measurement device, an area statistic device and a dehumidifying drive device; the window body consists of a stainless steel frame, a fence and a screen window, wherein three glass sheets are embedded in the stainless steel frame, and an non-vacuum state is formed between every two glass sheets of the three glass sheets; the water drop measurement device is used for peeling off one or multiple water drop targets from an interlinked operating image according to the preset water drop shape; the area statistic device is connected with the water drop measurement device and used for adding up the area proportion of one or multiple water drop targets accounting the interlinked operating image, and sending a dehumidifying control signal when the area proportion value ishigher than the preset proportion threshold; the dehumidifying drive device connected with the area statistic device is used for determining corresponding power of an air blower according to the areaproportion when receiving the dehumidifying control signal.