In this paper, the research on fatigue property of M22 high-strength bolt in grid structure with bolt-sphere joint was carried out. The Amsler fatigue testing device with stable and reliable performance was used for testing the fatigue property of high-strength bolts. By conducting comparative analysis between testing results and some domestic related results, the reasonable constant fatigue design method of high-strength bolt has been reached in this paper. The research result can provide effective reference for the design and fatigue calculation of high-strength bolt.