According to the charging data of electric vehicles in a southern city, this paper derives the distribution patterns of charging start time, electric quantity and charging power of each type of electric vehicle on different date types, and uses Monte Carlo algorithm to calculate the charging load of each type of electric vehicle on weekdays and rest days in the city in 2021.The results show that the charging load of electric private cars is higher on rest days than on weekdays during lunchtime and early morning; the charging load of electric taxis in the city is 60.42% and 58.55% on weekdays and rest days respectively, which is always the largest among the three types of vehicles. There is a large difference between the charging load curve for electric private cars on weekdays and rest days. The total grid load peaks at 19:00. This paper verifies that the large-scale introduction of electric vehicles increases the peak and peak-valley differences on the grid, and at the same time fits the charging behavior data into formulas, with the aim of providing assistance in the construction of future grid expansions and the control of orderly charging of electric vehicles.