Based on the truss arch of Xiangtan 4th Bridge, we made fatigue property test on concrete filled steel pipe K-joints of three different specifications, and calculated the amplitude of fatigue load of concrete filled steel pipe K-joints with hot-spot stress approach in this paper, which presented that hot-spot stress approach can be used to assess fatigue life of concrete filled steel pipe, and fatigue property of concrete filled steel pipe K-joints was obviously better than that of steel pipe K-joints. Moreover, the S—N curve of concrete filled steel pipe K-joints proposed by this paper would be of referential significance for building design criterion of fatigue life of concrete filled steel pipe K-joints.