Abstract: Wind power gearbox is an important part of fan transmission chain，in which the high-speed gear working environment is complex and variable.The failure and damage of wind power gearbox is easy to cause gearbox fault，or even bring catastrophic consequences and stop.Real-time status monitoring and fault diagnosis are particularly important to ensure normal operation of the fan.There were many research methods for fan fault diagnosis based on vibration signals，but the existing methods were not universal for specific types of fans.Therefore，based on classification and summary of gear failure characteristics，vibration signal gear was selected to analysis broken failure in high speed.Original signal was de-noised by wavelet transform，and edge frequency band characteristics were effectively identified to reflect the degree of gear failure.Then frequency domain characteristics were obtained by frequency spectrum transformation to reflect type of gear failure.Results showed that the upper amplitude of time domain has periodic impact and the period was reciprocal of rotational speed.In frequency domain，frequency of 5 times of frequency of revolution has been greatly increased，even reaching 127 times.At high rotation speed，asymmetry of mesh frequency band of 2 times side frequency was more obvious，and amplitude of 3 times frequency increases by 4.4 times.The failure of broken teeth will cause resonance phenomenon in frequency range of 1 200 Hz to 1 500 Hz of this type of fan.