The fault of wheelset bearing is one of the most important factors which is deangerous to the satfy of the train running. And the key problem that should be solved firstly is the accur ate measurement method for the high speed heavy haul locomotive. Since there are some discontinuity points in the amplitude of the vibration signals when the wheelset bearing is abnormal, a method for analyzing the vibration acceleration signals which come from the wheelset bearing by using the spectrum zoom is prsented. The experiments indicate that the abnormity of wheelset bearing high-accuracy detection can be realized by using this method, and this method can detect the abnormity effectively compared to the commonly used methods.