As the key assembly of new energy vehicles, the noise and vibration, and harshness (NVH) performance of integrated electric drive system directly affects the driving quality of new energy vehicles. In this paper, the vibration noise characteristic test of 3in1 electric drive system is carried out in the semi-muffler chamber. In order to compare and analyze the difference between 2in1 and 3in1 electric drive system NVH performance, the power electronics unit (PEU) in the 3in1 system was removed and placed on the ground away from the platform, and vibration noise test was carried out. In order to analyze the difference of NVH performance between 2in1 status and 3in1 status, the PEU in the 3in1 system was removed and placed on the ground far away from the bench, and the NVH test was carried out. The microphone signal at 1m position and the vibration acceleration signal of the key structural surface of the system are measured experimentally. The research results show that the addition of PEU enables the 3in1 electric drive system to generate new resonance frequencies at 350Hz, 570Hz, 1120Hz. At the same time, the integration of PEU improves the noise of the 3in1 electric drive system at the resonance frequency caused by the sub-frame at 50Hz, and improves the noise at the resonance band caused by the motor cover near 2350Hz. Compared with the 2in1 electric drive system, the noise of the 3in1 electric drive system with PEU is greater than that of the 2in1 electric drive system in the main order, and the A-weighted sound pressure level of the noise of the 3in1 electric drive system increased by up to 17-20 dB at 500-2000rpm and 7-10 dB at 10000-13000rpm.