Abstract: In this paper, the response signal of current-carrying long straight metal pipeline is discussed by numerical simulation, and the influence of current intense and pipeline buried depth on the amplitude of the response signal is analyzed. Then, through field experiment, the detection effects of single-end connection method and double-end connection method are compared. The results show that, under the same gain, the detection effect of double-end connection method is obviously better than single-end connection one. When it is far away from the charging point, the change of gain parameter cannot change the weak signal characteristic of single-end direct connection method in nature. Through engineering application, this paper discusses the idea of combining induction method and direct connection method in the detection of hidden metal pipeline, summarizes the technical route, and realizes the location detection of hidden pipeline.