The stiffness calibration tests for test system and the complete uniaxial tensile tests for concrete were done on a MTS322 electro hydraulic servo testing machine, and the effects of spherical hinge equipment on the complete uniaxial tensile test for concrete were analyzed. The results show that the stiffness of loading system is greatly reduced by spherical hinge equipment, in addition, the relation between the displacement of actuator and the deformation of concrete specimen does not follow a linear rule. Besides, it can not make the fracture process of concrete stable by increasing the stiffness of spherical hinge equipment in a limited range when using the displacement of actuator to control loading. Only using the maximum strain of concrete specimen to control loading, a complete uniaxial tensile stress strain curve of concrete can be achieved.