The invention belongs to the field of underground pipeline detection, and particularly relates to a pipeline detection and positioning method based on buried iron pipeline magnetic field indirect detection. According to the specific realization method, three-axis magnetic field sensors are used for forming a linear detection array, abnormal distribution of magnetic induction intensity near the surface is detected in a detected area along a linear detection path, a detection magnetic field tri-component far away from the magnetic induction intensity abnormal peak point in the detection path and little influenced by the magnetic abnormal condition is used as a background magnetic field, the background magnetic field tri-component is subtracted from a detection magnetic field tri-component on each measurement point, vectors are solved as magnetic fields, and the peak connection of the obtained magnetic fields detected and calculated by each path of probe is used for positioning horizontal distribution of the underground pipeline. The pipeline is accurate to detect and position, the equipment cost and the use cost are low, and the instrument is easy to make.