The invention discloses a power grid disaster early-warning method and system. The method includes the steps of building a corresponding relation of a power grid disaster and routine meteorological phenomena to obtain a power grid disaster early-warning standard, storing the power grid disaster early-warning standard, obtaining weather forecast information of the region where a power grid to be detected is located in real time, comparing the weather forecast information with the power grid disaster early-warning standard to obtain power grid disaster early-warning information of the power grid to be detected, and generating and publishing a power grid disaster early-warning result according to the power grid disaster early-warning information.