The invention discloses an electric vehicle automatic identification system and method for an alternating current charging pile. The electric vehicle automatic identification system comprises a first communication device and a second communication device. The first communication device is installed on the charging pile. The second communication device is installed on an electric vehicle. A charging gun of the charging pile is simply inserted into the charging interface of the electric vehicle when needed, wherein the charging interface is an alternating current charging interface. The alternating current charging interface of the electric vehicle is used as a communication interface to communicate. The installation of a conductive wire is simpler. Moreover, the first communication device reads the identity information of the second communication device, which can automatically match to determine whether it can be charged and conduct automatic deduction. The charging process is simple, and the entire process is automatically completed, saving time and effort. There is no need to punch cards or scan a two-dimensional code through a phone to charge each time, which is convenient and quick. Users do not have to worry about charging inconvenience to individual charging or group charging due to the loss of charging cards.