The invention discloses a charging system and a charging method of a charging-replacing electric vehicle. The system comprises a battery consumption measuring module of an electric vehicle, a chargingand replacing control module of the electric vehicle, a BMS of the electric vehicle, a VCU of the electric vehicle, a locking device of a power battery pack of the electric vehicle, a charging and replacing station server, a charging pile, a replacing device, a data terminal server and a mobile phone customer service terminal. At work, the charging and exchanging station server sends out power consumption inquiry information to the charging and exchanging control module of the electric vehicle, the charging/replacing control module inquires the output electric quantity information of the power battery stored in the battery electric quantity measuring module, and transmitting the power quantity information to the charging and replacing station server, the charging and replacing substationserver calculates the cost according to the power quantity and transmits the cost information to the data terminal server, the data terminal server sends the payment information to the mobile phone customer service end, the vehicle owner pays the cost through the mobile phone customer service end, and after the payment is completed, the vehicle owner selects charging or power exchange service.