The reaction of three kinds of MgO, Al2O3 and MgO+CaO based tundish gunning materials (GM) with molten steel were studied, their effects on the contents of total oxygen, total nitrogen, Al, Ti and Si in steel, and composition, quantity and size distribution of inclusions examined, and the infiltration and erosion of gunning materials at the interface with steel analyzed. The results show that compared with MgO and Al2O3 based GM, the use of MgO+CaO based GM could control the total oxygen content and inclusions in steel better at 1550℃, leading to the improved steel cleanliness with the final oxygen content of 8.5′10-5, and the reoxidation of steel was reduced and the formation of fine inclusions was improved, leading to <1 mm inclusions with 98.13% proportion. Al and Ti were firstly oxidized, and then Si and Mn. The erosion of Al2O3 based GM was mainly caused by wearing, and that of MgO based GM by molten steel infiltration. The use of MgO+CaO GM could reduce the secondary pollution of molten steel, which was more conducive to the production of clean steel.