Pulsed eddy current thermography has great advantages in defect detection in conductive materials.In this paper,a mathematical model of induction heating is established with the electromagnetic induction and heat transfer theory.The finite elements method is used to analyze the mechanism of crack detection using electromagnetic stimulated thermography.The distribution of eddy current and temperature field near the crack slot and notch are simulated with COMSOL in magnetic and non-magnetic materials respectively.Through the analysis of eddy current density near the crack and temperature curve,the best observed time and temperature response of crack detecting in magnetic and non-magnetic materials are found.That provides theoretical guidance for the quantitative detection of cracks in the next step.