AC induction machines are widely used in electric servo drive, information processing, transportation and other fields. However, the unexpected faults can generate due to the unreasonable inputting current or voltage and the harsh working environment in AC induction machines, which cause the serious threat for the normal operation and the operator’s safety. Therefore, timely diagnosis the faults in AC induction machines is an effective way ensure the AC induction machines working in health condition. Magnetic field is the basis of energy conversion of motor, eddy current exists in motor and has direct influence on electromagnetic field distribution. Hence, we setup the 2D numerical model of the AC squirrel-cage asynchronous induction machine by using COMSOL Multi-physics according to finite element method, Then, the magnetic flux distribution of induction motor with three different faults (Rotor eccentricity, Rotor bars breakage, crack in shaft), which commonly occurs in engineering are simulated. Based on the numerical simulation, the influence of the different faults on the magnetic distribution are discussed in detail. The investigation in this paper is beneficial to find a nondestructive fault diagnosis approach to the induction machine.