Abstract: Based on the ANSYS finite element analysis software, the heating phenomenon of weld cracks under ultrasonic excitation was simulated. The effects of ultrasonic excitation amplitude, frequency, direction and weld height on the crack temperature rise are analyzed qualitatively. In addition, the feasibility of ultrasonic infrared detection of weld cracks is verified by comparing the results of ultrasonic infrared thermal imaging and penetration detection, and the accuracy of finite element analysis is verified by experiments. This study shows that ultrasonic infrared thermal imaging has potential application value in non-destructive testing of austenitic stainless steel weld cracks.