The vibration characteristic of gearbox of high-speed train under different working conditions is studied. With a gearbox of a certain type of high-speed train as the object, the main influence factors of vibration are studied by the method of combining the modal test and bench test. The results show that the vibration of the gearbox of is greatly affected by the rotational speed. The characteristic frequency of the gearbox will coincide with the modal frequency of the gearbox housing to cause resonance. The vibration of axial direction is significantly affected by the modal shape of gearbox housing. Through the experimental analysis, the vibration characteristics of the gearbox are obtained, a foundation for the analysis and structural optimization of the high-speed train is provided.