The invention discloses a monitoring and early warning method of a transmission tower under a rainfall-induced landslide disaster. The method comprises a step of obtaining historical rainfall information and rainfall forecast information and determining the level of a rainfall impact factor FR, a step of determining an initial state impact factor FG of the transmission tower if the transmission tower is located on an upper side of a landslide body, a step of determining a damage differential impact factor FT of the transmission tower if the transmission tower is located on a lower side of thelandslide body, a step of calculating a danger index of the transmission tower, and a step of determining a landslide hazard warning level of the transmission tower based on the danger index F of thetransmission tower and issuing disaster warning information. The invention provides a new technical method for the failure early warning of the transmission tower induced by a rainfall landslide, andthe accuracy and effectiveness of the early warning are improved.