It is of great significance to research the hierarchical rules of the factors influencing the granulation performance of iron ore powder for granulation and sintering production. In this paper, through detecting the performances of 11 kinds of iron ore powder, conducting the granulation test at different granulation levels, the types of inter-particle forces are analyzed. In addition, the adhesion index is used to characterize the granulation effect of ore powder, judge the relative size of the intergranular force, and analyze the influence of various factors on the expression of intergranular force. The results show that the intergranular forces affected by the granulation process of iron ore powder include such 3 kinds as the viscous force generated by iron ore powder itself, the adsorption force generated by molecular water and capillary water, and the resistance generated by the angular angle of the ore surface, among which the viscous force is greater than the water adsorption force and angular resistance. The granulation of viscous iron ore powder is affected by the above 3 forces at the same time, mainly by viscous force. During the granulation of non-viscous iron ore powder, the adhesion index is positively correlated with the spherical index (K is used to represent the water adsorption force) and the macroporosity (the force generated by D_big is used to represent the surface roughness). Moisture, particle viscosity, particle grade, hydrophilicity and roughness are the main factors affecting the expression of inter-particle forces, and the influence of the main factors on the granulation performance of iron ore powder has an obvious hierarchical structure.