The finite element model of FT80 tractor’s cab is established by using FEM software ANSYS. Then, using the acoustics software SYSNOISE, the soundsolid coupling analysis with the combination of FEM and intermediate BEM is carried out. By means of the intermediate BEM, the acoustic characteristics of the cab are computed and analyzed. The sound pressures of neartheear sound fields of three cases—empty cab, cab with a chair in it, and cab with a chair and a driver in it—are computed and compared. The acoustic contribution of the chair and the driver in the cab is calculated and analyzed. It is proved that the chair and the driver have some influences on the internal noise of the cab. These influences should be considered in the modeling.