Aiming at the problem of excessive noise inside the vehicle when the axial fan is working at idle air conditioning, a transfer path analysis model is established, and the trial and analysis method of fan vibration transmission rate is studied. Furthermore, the coupling excitations of body end connection points are obtained to ensure the accuracy of transfer function by matrix inversion method. The results show that the largest ratio of noise inside the vehicle is along the y direction of the fan assembly left mounting point of the upper beam, and the reason is that the modal frequency of fan assembly coincides with the excitation force frequency to resonance. The noise problem inside the vehicle is solved by avoiding excitation force frequency and fan assembly model frequency for optimizing the dynamic stiffness of fan assembly vibration isolator. The research of transfer path provides ideas and basis for the noise control of automotive fan.