In order to use the three-phase asynchronous motor on the mechanical equipment for a long time, it is necessary to place it stably and make it operate smoothly. Then, for the phenomenon of motor vibration, it is necessary to find out the cause, otherwise more motor faults will easily occur and damage the motor. This paper specially explains the way to find out the vibration cause of three-phase asynchronous motor: 1. Before the three-phase asynchronous motor is shut down, first check the vibration of each part with a vibration meter. For the parts with large vibration, test the vibration value in three directions of vertical horizontal axis in detail. If the foundation screw is loose or the bearing end cover screw is loose, fasten it directly, and then measure the vibration after fastening to see whether it is eliminated or reduced. 2. Secondly, check whether the three-phase voltage of the power supply is balanced and whether the three-phase fuse is burnt out. The single-phase operation of the motor can not only cause vibration, but also make the temperature of the motor rise rapidly. Observe whether the pointer of the ammeter swings back and forth. When the rotor is broken, the current swings. 3. Finally, check whether the three-phase current of the three-phase asynchronous motor is balanced, and contact the operator to stop the motor in case of any problem, so as to avoid burning the motor. If the vibration of the motor is not solved after the surface treatment, continue to disconnect the power supply, untie the coupling, and make the motor mechanically separate from the load connected to it, single turn the motor. If the motor itself does not vibrate, it means that the vibration source is caused by the coupling is not aligned or the load machinery. If the motor vibrates, it means that the motor itself has problems. In addition, the power-off method can also be used to distinguish the electrical cause or mechanical cause. When the power is cut off, the three-phase asynchronous motor immediately does not vibrate or the vibration is reduced, which indicates that it is the electrical cause, otherwise it is the mechanical failure. Three phase asynchronous motor vibration reason search, if you are engaged in the motor industry, or have relevant experience or views, welcome to share your views.