Theory and practice show that the observation of the transient magnetic field in the TEM has more advantages than that of the induced EMF. With the application and improvement of the hightemperature superconducting technology, the direct observation of transient magnetic field signal has become a reality in the TEM. However, the retrieve interpretation method for transient magnetic field data has become an urgent problem. In this paper, drawing on the interpretation method of the induced EMF, the authors made an overall explanation of the definition of apparent resistivity based on a study of the transient magnetic field and probed into the TEM transient magnetic field for PSEUDO2D inverse technology. From the theoretical model and the measured data, the authors have verified the practicality of the method, which can provide technical support for the development of the hightemperature superconductor TEM method.