An experiment about circular steel pipes subjected to cyclic loading was designed to study the spatial hysteretic behavior and obtain the constitutive model of steel considering damage cumulation.The experimental device was applicable for three-dimensional loading.Five loading modes were performed on a total of 30 specimens with different cross sections and heights with consideration of different slenderness ratios and loading modes for the circular steel pipe.The spatial loading of the circular steel pipe was successfully simulated by optimizing the experimental device,and the hysteretic curves composed of loading and displacement as well as the strain curves of typical position were obtained.Results show that the experimental device can meet the need of the experimental accuracy for its good stability.The circular steel pipe has excellent hysteretic behavior and can keep good capability of energy consumption even at great displacement action.The study lays the foundation of the subsequent research on constitutive model about steel.