Abstract: Quantitative measurement of defect depth is an important application of pulsed infrared nondestructive testing. The calculation principle of peak second derivative of the temperature decay curve in the log scale was analyzed based on one-dimensional heat conduction model. The stainless steel sample which has six flat bottom holes with same diameters and various depths at the back surface was used. Ansys was used to simulate the process of pulsed infrared nondestructive testing. The depth of defects were calculated by method PSDT. The results of Ansys and pulsed infrared nondestructive testing were compared and analyzed, which indicate that the Ansys model in accordance with the experiment. This research provides theoretical basis for the quantitative study of infrared nondestructive testing.