Abstract: Groups of triaxial and torsional coupling cyclic shear tests on onboard iron ore concentrate are carried out by hollow cylinder apparatus to study the deformation and mechanical properties of iron ore concentrate subjected to cyclic loading. By analyzing curves of strain, dynamic strength and pore pressure, the influence factors on fluidization of the iron ore concentrate are explored. The experimental results show that the moisture content is the key factor for the dynamic behaviors of the iron ore concentrate. There is an critical moisture. When it is above the critical moisture content, the sample will be slowly destroyed under a small dynamic stress and long enough vibration times. The sample with high moisture content will be destroyed rapidly even under a small dynamic stress. Compared with that of the dynamic triaxial tests, the dynamic strength by hollow cylinder apparatus decreases rapidly with the increase of the moisture content. It has certain practical significance that the experiments provide safe moisture content range for the onboard iron ore concentrate.