Abstract: The surface crack of metallic materials can be detected efficiently and accurately with pulsed eddy current thermography. The detect results are very different with the change of excitation parameters and physical properties of materials. In this paper, with the building of a twodimension model for induction heating, the surface temperature rise and ratio of temperature rise are chosen to analyze the induction heating rule of magnetic and nonmagnetic materials, that is, 45 steel and 202 stainless steel, as the excitation duration and frequency changes, then the differences of the distribution of eddy current and temperature and the results of various excitation parameters on crack detection between the two materials are compared, which provide a guidance to optimize the excitation parameters of ferromagnetic and nonmagnetic materials for practical detection.