In municipal construction, to avoid casualty and property loss the buried pipelines beneath the construction site should be accuracy located. There are many locating method such as magnetic method, electromagnetic method, infrared thermography, ground penetrating radar, acoustic location system etc. All these methods mentioned above can only make an acceptable result at the depth down to 5 m. In this study, improved frequency domain electromagnetic method (FDEM) is used to locate deep buried metal pipeline (>10 m). In this method, the mathematic model is rebuilt and special probe with the diameter of 20mm is designed. It was conduct by two steps. First, Using the regular FDEM method to estimate the approximately depth and horizontal location. Then, the electromagnetic field induced by metal pipeline is measured by the probe in the borehole drilled within 5 m away from the projection of pipeline on the ground and the full curve inversion method is used to give the accuracy depth and planimetric position. Result show that the improved FDEM method can detect the deep buried (>10 m) pipeline with the relative accuracy of and planimetric position with the relative accuracy of . With the advantage of high accuracy and trenchless, it can improve efficiency by replacing excavation verification in the buried pipeline on site investigation. Regular FDEM method usually locates the underground metal pipeline by measuring the eigenvalue of specific frequency electromagnetic characteristic curve upon the vertical direction. Improved FDEM method combine the eigenvalue method and full curve inversion method. Furthermore by detecting electromagnetic field in the borehole the detection line is closer to the pipeline and the interference is less which leads to a high S/N. That why the improved FDEM have a high accuracy in deep buried metal pipeline locating. On the other hand, the probe is designed to well match the current instrument, so it need not to add special receiver which make the method more economical to apply. The location without error of deep buried pipeline especially the deep buried oil and gas metal pipeline is vital. The improved FDEM could provide an effective way in locating the deep buried metal pipeline.