Based on the theory of acoustic elasticity, the relationship between ultrasonic body wave (shear wave and longitudinal wave) and stress is studied, and the technology of bolt axial stress detection is analyzed. In order to ensure the accuracy of the detection value and achieve traceability, the calibration technology of bolt axial stress ultrasonic body wave detection is studied. The temperature compensation algorithm and the precise measurement algorithm of acoustic time difference are designed by means of spontaneous selfcollection. The feasibility of the absolute calibration method of the axial force meter is verified by experiments. The ultrasonic shear and longitudinal wave testing and calibration system for bolt axial stress is established, which is applied to the axial stress testing of buildings, bridges and power stations.