The risk evaluation of precipitation enhancement in flooding season over the reservoir area in Qinhuangdao is conducted by using the method for computing the increased precipitation developed by the Weather Modification Office of Hebei Province, based on the precipitation data of the area around two big reservoirs of Qinhuangdao, in case of the largest rainfall in history over the Yanghe and Taolinkou drainage areas resulted from precipitation enhancement operation. The result shows that precipitation enhancement operation will not cause danger to reservoirs. According to the analysis of climate change, the precipitation enhancement aiming to increase the water capacity of reservoirs in flooding season is an effective approach.