To address the issues of increased energy consumption of electric vehicles，grid load，and peak valley difference caused by high humidity and temperature in the rainy season in Southern China，a charging price model based on peak valley difference is proposed to stimulate electric vehicles to participate in demand response，so as to stabilize the peak valley difference of grid load and improve the economic benefits of electric vehicle users.Firstly，the Monte Carlo simulation is used to analyze and predict the disordered charging load of electric vehicles，considering factors such as high temperature and humidity during the rainy season in Southern China.Then，a peak-valley differential charging price model is built to minimize the peak valley difference of the power grid and the user charging cost.Lastly，simulation analysis is conducted on the model using the MATLAB application.The research shows that the proposed model considering the high humidity and temperature of the rainy season in Southern China is more accurate.The model can reduce the peak valley difference rate，improve the economic benefits of users，and realize the smoothing and optimization of grid load.The research provides a reference for a new electric vehicle charging scheduling.