The invention proposes a high power charging system for an electric car. The high power charging system comprises a power cell, a charge connecting device, an external power supply device, and an electric control device, wherein the power cell is arranged inside the electric car; the charge connecting device comprises a power supply plug and an automobile plug; the external power supply device is connected with the power supply plug of the charge connecting device; the charge control device is arranged inside the electric car, connected with the power cell and connected with a car plug of the charge connecting device; and a modulated pulse-width modulation (PWM) wave signal is transmitted by the charge connecting device between the charge control device and the external power supply device, so as to achieve communication of the charge control device and the external power supply device. By adopting the system, uniform switching of a working state of each system can be achieved; each split system of the car is harmonically controlled; and the high power charging system is strong in compatibility. Meanwhile, a control method of the high power charging system for the electric car is also provided by the invention.