The charging management mode of electric vehicles affects the planning and design of the power distribution capacity of charging facilities. Orderly charging of electric vehicles in residential areas can achieve peak load shifting, improve the utilization rate of distribution transformer and increase access capacity of charging facilities. In this paper, a probability model of charging load in residential area is established based on the charging behavior of residents, and two key parameters of charging load, simultaneous rate and stack rate, are proposed to characterize the changing characteristics of charging load. Furthermore, the planning models of the electric vehicle charging load and residential electricity load are established, and then the relationship between the transformer load rate and the maximum permeability of electric vehicles in residential areas is obtained through mathematical analysis to quantitatively evaluate the potential of orderly charging of electric vehicles in residential areas. This paper can provide scientific reference for lean management of charging load and reasonable configuration of distribution capacity of charging facilities in residential areas. This work is supported by Science and Technology Project of China Southern Power Grid Co., Ltd. (No. ZBKJXM 20160003).