Abstract: To solve the problem of low frequency vibration in the cab of electric vehicle, a finite element model of cab with four isolators was established, and the nonlinear spring damping element in three directions was proposed to replace the vibration isolators. The constrained modal analysis was carried out. According to the results of modal analysis, the causes of cab shaking were discussed, and on this basis, two methods were presented to improve the vibration isolator design and reduce cab shaking. Considering the actual application condition, a hydraulic damping rubber isolator was designed and analyzed to improve the ride comfort of the cab. In addition, the installation position of the isolator was adjusted to reduce the vibration of the cab effectively. Modal analysis results show that the frequencies of the modes are increased, and the fourth order vibration mode can be transformed to the local vibration of the rear wall of the cab. Finally, the vibration analysis of cab isolation system was carried out based on finite element simulation. The results show that the vertical amplitude of cab vibration isolation system under low frequency pavement displacement excitation is obviously reduced after adjusting the installation position of the isolator.