Aiming at the problem of tough extraction about tiny wear particle in the signal output on the inductive debris detection sensor caused by the interference of noise, a new method of noise reduction and extraction of characteristic information to the oil debris signal based on variance stability is proposed in this paper. Making use of the discrepancy in the pre-processed signal about various components, the variance stability has been measured in the first stage. Then, the adaptive threshold is extracted according to the statistical features of normalized variance stability, and the pre-processed signal is segmented by the threshold on this basis. Finally utilizing the characteristic identification index of target signal to further realize the recognition and counting of all debris induced voltage signals. Experiment show that the proposed algorithm can successfully extract the induced voltage signal generated by the tiny debris with the equivalent diameter of 50 μm. Compared with the traditional noise reduction algorithm based on the decomposition principle, the new method proposed in this paper can effectively eliminate the background noise in the detection signal, and its advantages of protecting the morphological characteristics of debris signal can ulteriorly improve the detection ability of small wear particle in the intense interference environment.