According to strong proponent of energy conservation and emission reduction, the development of new energy vehicles has been upgraded to the national strategic level in "Twelfth Five-Year Plan" period, and it becomes the main theme of Chinese automobile industry. And the planning of electric vehicle battery-switch station (BBS) has a great impact on the popularisation of electric vehicle and the security of power system. For reasonably planning of the location and sizing of the BBS, an optimization planning cost model and a new demand model of battery-switch station are proposed. This demand model is based on analysis of customers' characteristics. And in the optimization cost model, the objective function includes such variables as network loss cost, building cost and running cost of a particular battery-switch station, electrovalence and so on. Its constraints include the acceptable load power of the power system, the demand of electric vehicles, and the limitation of service territory of the BBS and so on. Finally, a practical example is carried out to demonstrate the performance of the demand model and the planning method.