Bit-field separation is an important part of gravity and magnetic data processing． In order to extract different levels of anomaly information better，this paper introduces the dual-tree complex wavelet multi-scale separation to the processing of bit-field data firstly and uses the geological model of different buried depth to verify its feasibility． Finally，the dual-tree complex wavelet is applied to the aeromagnetic anomaly in Jinchuan copper nickel mining area． The results show that the method can effectively separate the anomaly information of different scales and analyze the output results with relevant geological data．