Abstract: In this paper the impact of process parameters such as acidic material sintered grain size,carbon ration and alkalinity on the microstructure of shunt granulation sintered ore had been studied. It was found out that when particle size range of acidic materials expanded,material layer permeability improved,calcium ferrite content increased and mineral phase structure became more uniform. At lower alkalinity,sinter bonding phase was dominated by calcium silicate and glassiness. As alkalinity increased,perovskite content increased to a peak level and then decreases. When alkalinity reached to 2.02,calcium ferrite content increased greatly and bonding phase were mainly calcium ferrite and glassiness. With the increase of carbon ratio,calcium ferrite and hematite contents decreased,while perovskite and ferrous contents increased,which caused the increase of the drum strength of sinter and RDI index,and drop of reducing ability. Based on the research results the suitable carbon ration was chosen at 4.2% for shunt granulating process.