Located in Xinyu City, Jiangxi Province, the Ganzhong iron deposit is a sedimentary metamorphic iron deposit. As the country rock in this area is non-magnetic, we have the base of physical properties to implement magnetic survey. The iron formation is thin and deep in this area. So far, the interpretation of the magnetic data has not achieved good results. The previous work was mainly focused on the geological exploration and drilling. In this paper, the authors first studied the status of the geological work in the study area, and then used the wavelet multi-scale decomposition method to extract the deep field anomaly. The method of tilt-angle and the Theta Map was also employed to identify the boundary of the iron formation and, as a result, five prospecting areas were delineated which have good metallogenic potential. In addition, the authors applied meticulous inversion and interpretation along No. 62 exploration line of Songshan area based on the borehole data of ZK6209 and provided a quantitative interpretation result. It is pointed out that three-component borehole magnetic survey is an effective way to find the deep iron formation. This paper provides some new ideas for the deep and peripheral prospecting in the Ganzhong iron deposit.