The invention relates to a vibration acceleration measurement-based wind power generation unit transmission system fault alarm method which comprises the following steps of collecting a vibration acceleration signal at an important part of a wind power generation unit transmission system firstly, then constructing an acceleration signal-based compound index M, wherein the compound index M in the method is obtained by synthesizing an effective value of the vibration acceleration signal and a kurtosis index, comparing the obtained compound index M with a preset alarm threshold MThreshold, and finally, judging a running condition and a fault level of the wind power generation unit transmission system through a comparative result. Shown by analyzing actually-measured vibration acceleration data of multiple groups of the wind power generation units, the method provided by the invention has remarkable promotion action on the sensitivity and the accuracy of a fault alarm of the wind power generation unit.