According to the characteristics of outage, the wind turbine is divided into two parts, namely the electromagnetic system and the machinery system. The failure rate model of electromagnetic system based on the grid voltage and frequency is established considering the impact of the grid operating conditions on the wind turbine outage, and the failure rate model of machinery system based on the wind speed is established considering the impact of the weather on the wind turbine outage, then the wind turbine outage rate model based on operating conditions of grid and weather can be obtained. The simulation of 1.5 MW wind turbine is carried out in Matlab, and the outage rate of wind turbine under diffident operation conditions is given. The model can reflect the effect of wind turbine outage rate on the grid operating conditions and external wind speed and can accurately characterize the level of safety and reliability of the wind turbine under real-time operation.