Aiming at the excessive vibration issue of a crane frame, the vibration damping performance of both engine and transmission mounts was evaluated and optimized with experiment and simulation. Firstly, test detection and vibration acceleration spectrum analysis of 20 points were conducted to investigate the cause of excessive frame vibration through modal analysis. Calibration of the simulation process was completed based on the test data. Secondly the vibration damping performance of both engine and transmission mounts were optimized with the simulation process. Finally, the proposed optimization scheme was verified through testing. The results show that the vibration amplification of the frame is caused by the resonance between the mount natural frequency and the excitation frequency of the transmission near 450Hz and 690Hz. Through optimization design of the transmission mounts, the resonance issue of the transmission is effectively improved and vibration transmission rate meets requirement of less than 70%.