The weight reduction design of vehicle permanent magnet synchronous motor (PMSM) brought about more serious vibration and noise of the motor. An accurate modal calculation was the basis for the study of the vibration and noise characteristics of PMSM. The finite element method was used to perform the modal simulation of the PMSM. Through the reasonable simplification and equivalence of the motor model, the first 6 orders natural frequencies and corresponding modes of the motor under the free state were calculated. After that, the accuracy of the finite element model was verified by the hammering modal experiment of the prototype.