The invention discloses a disaster-causing precipitation threshold value division method and system for a precipitation type landslide hazard of a power grid channel. The method comprises the steps that the geological condition evaluation data, the topographic data, historical daily precipitation data of about 20 years of the meteorological station and the geologic hazard historical data in the power grid channel are acquired, wherein the data are obtained through general investigation of the land department; according to the geological condition evaluation data and the topographic data of thecounty-level administrative region where the power grid channel passes, the geologic hazard danger level of the section of the power grid channel is determined; based on the historical daily precipitation data of about 20 years of the meteorological station, the lowest disaster-causing threshold value of short-time heavy precipitation and the lowest disaster-causing threshold value of accumulatedprecipitation are determined; and according to the geological condition level of the power grid channel, the lowest disaster-causing threshold value of short-time heavy precipitation and the lowest disaster-causing threshold value of effective accumulated precipitation, disaster-causing precipitation threshold value division of the precipitation type landslide hazard of the power grid channel iscarried out. By means of the method and system, the prediction and pre-warning capacity of the precipitation type landslide hazard of the power grid channel can be effectively improved.