In order to solve the problem that the position of each phase core wire is difficult to determine during the process of the three-core power cable quality inspection , a method for determining the position of each phase core wire in the three-core power cable is proposed. Specifically, by arranging two magnetic sensors symmetrically on the surface of the three-core power cable, after a single-phase core wire in the three-core power cable is given an current excitation, magnetic sensors are used to measure the tangential component of the magnetic flux density at the position. Based on the measured values of the two magnetic sensors, and using the Ampere loop theorem and the geometric relationship between the position of the single-phase core wire center and the position of the magnetic sensors, the distance from the single-phase core wire center to the three-core power cable center and the angle between the line connecting the single-phase core wire center to the three-core power cable center and the y-axis are solved, ie, the position of the single-phase core wire. By applying current excitation to the three-phase core wires separately, the position of the three-phase core wires can be determined, thereby realizing the determination of the position of each phase core wire in the three-core power cable. The results of electromagnetic finite element simulation and analytical model calculation show that this method has high accuracy and has guiding value for improving the production level and quality inspection of the three-core power cable.