Corundum spinel castable was prepared using tabular corundum as aggregates, white fused corundum powder, spinel powder and alumina powder as the matrix, pure calcium aluminate cement as a binder, and extra adding calcium chloride (0, 1%, 2%, and 3%, by mass). The effects of the CaCl2 addition on the cold physical properties, the hot strength, the thermal shock resistance and the microstructure of the castable were studied. The results show that, for the corundum spinel castable fired at 1 550 ℃, with the increase of the CaCl2 addition from 0 to 3%, the cold strengthes first increase, then decrease, the apparent porosity increases, the volume density decreases, and the linear change rate first decreases and then increases, while the overall change is not significant; however, the hot modulus of rupture and the thermal shock resistance are obviously improved. This is mainly due to that, CaCl2 is evenly distributed in the castable in the form of solution, and reacts with Al2O3 to form small flake CA6 crystals, which evenly distributed in the sample matrix strengthening and toughening the material.