NVH performance is one of the most important quality properties of a vehicle, especially for improving the comfort of new energy vehicles. This paper takes the NVH problem of a new energy vehicle as an example to explain how to deal with the noise problem. It is found that there is a howling noise in the starting process of the testing vehicle, which is an NVH problem. This will lead to reduced ride comfort, and ultimately affect vehicle quality and car sales. In order to find out the cause of the howling noise, this paper analyzes the fault problem by means of elimination analysis, bench test and the measurement of vibration noise of the real vehicle. It is found that there are inconsistencies in the initial electric Angle and other parameters of the motor between the loading motor and the pre-calibration motor, which leads to the howling noise. Finally, the starting control parameters of the motor are modified by the controller software to greatly reduce the howling noise. Through a series of analysis methods, the paper finds out the cause of the problem of howling noise, which to avoid the maintenance or replacement of hardware equipment of the vehicle and to improve the comfort of starting driving.