Abstract: Advantages and disadvantages of existing common fault line selection theories applied in leakage protection system of mine were analyzed. In order to solve problems of capturing and realtimely detecting transient signals in line selection method with transient signals of leakage faults in mine based on wavelet algorithm, an improved wavelet algorithm based on self-adapting filter technology was proposed. Disturbances and noise can be filtered effectively by the algorithm so as to get available information of zero-sequence current of fault line easily. The simulation result showed validity of the improved algorithm.