The method of fault diagnosis of rolling element bearing under a variable rotational speed and gear vibration noise based on chirplet path pursuit is proposed in this paper. At first, get the envelope signal of the original vibration signal based on Hilbert transformation and reduce the envelope signal under the condition of satisfying the sampling theorem. Then, extract the instantaneous fault characteristic frequency curve of the fault bearing by the chirplet path pursuit and resample the instantaneous fault characteristic frequency(IFCF) curve and rotation speed curve of the bearing. Finally, the fault diagnosis is completed by the comparison of the calculating instantaneous fault characteristic coefficient(CIFCC) with the fault characteristic coefficient(FCC) of the outer ring, inner ring and rolling element. It is proved that the method can not only detect the fault of rolling bearing, but also can determine the fault location by processing the simulation signal and experimental signal without filtration and order analysis.