Local wavenumber is a common method for magnetic data processing and interpretation. DEXP method can quickly image the spatial position of magnetic source, but the spatial imaging resolution is poor, easy to be affected by superposition ies, and easy to produce false information. In this paper, we propose to improve the local wave number DEXP method, and construct the variable depth imaging function by introducing the depth scale factor. This method can use the maximum value to reflect the field source space position, and estimate the magnetic source structure index through the extreme value and the inversion depth value. At the same time, combining different depth scale factors and different orders of imaging results can effectively improve the reliability and applicability of the method. Model tests show that the improved method has stronger spatial imaging resolution and more accurate estimates of field source parameters relative to the conventional local wavenumber DEXP method. Finally, the new method was applied to the ground magnetic anomaly in the youth point area of Nenbei Farm in Heilongjiang Province, and obtained good application results.