Abstract: The energy revolution has driven the rapid development of new energy vehicles, and the motor, as the core component driving the operation of new energy vehicles, once it malfunctions, it not only causes the vehicle to be unable to operate normally, but also may lead to safety accidents. The article is based on the working principle of the new energy vehicle motor (permanent magnet synchronous motor), analyzes its fault diagnosis process and methods, and takes the fault phenomenon of a domestic new energy vehicle motor as an example to specifically explain its diagnosis method and maintenance measures.