Abstract: Thermal Wave Nondestructive Testing(TWNDT) technology is used to detect defects of missile engine due to the disadvantages of traditional NDT methods. The process of TW testing is simulated by ANSYS for composite material with defects. The factors affecting the testing sensitivity of TWNDT is studied, including the size, depth, thermal diffusion coefficient of the defect, heating energy, surface convection exchange coefficient, surface radicalization and so on. The results of simulation show that TWNDT is a fast, effective, intuitive method, which can exact identify the defect depth, size and position.