Abstract: Infrared thermography is a nondestructive testing and evaluating technique that allows the non-contact inspection and quick monitor large area. There are different detection methods of infrared technology for nondestructive testing. In order to study the advantages and disadvantages of different detection methods, different detection methods of infrared technology for nondestructive testing were comparatively analyzed according to the theory of heat transfer. A two-dimensional heat conduction model was established. The temperature fields of the specimen under different heat source excitation conditions were simulated by using the established model, based on this, PT LT and PPT of infrared technology for nondestructive testing were numerically simulated, from the theoretical point of view, the merit and demerit of the three kinds of methods were compared, the best useful range of three infrared technology for nondestructive testing were obtained, a theoretical basis for the selection of detection method of infrared technology for nondestructive testing was provided.