DZ125 superalloys are widely used in aeroengine turbine blades because of their excellent performance and low cost. Aeroengine turbine blades are usually prepared by investment casting, of which ceramic shells are the basis. The wetting angle and interfacial reactions between the ceramic shell and superalloy are key factors affecting the quality and dimensional accuracy of superalloy turbine blades. In this paper, using white fused corundum powder, EC95 powder, and white corundum sand as raw materials and silica sol as a binder, the slurry composition of ceramic shell was designed for the directional solidification molding of turbine blades, and the ceramic shell was then prepared. The microstructure and surface roughness of the Al 2 O 3 -based ceramic shell were studied, and the wetting behavior and interfacial reaction between the Al 2 O 3 -based ceramic shell and DZ125 superalloy were analysed. The results show that the prepared Al 2 O 3 -based shell has a smooth surface and that the surface roughness is 1.973 μm. The Al 2 O 3 -based shell shows excellent inertia to the DZ125 superalloy, and the wetting angle reaches 119.54°. The DZ125 superalloy shows slight chemical sand adhesion, and the thickness of the sand layer is only approximately 0.5 μm. The chemical reaction products are mainly oxides of Ta, Cr, W and Ti. The slight chemical sand adhesion of the DZ125 superalloy is attributed to not only the smooth surface of the Al2 O3 -based shell but also the excellent nonwetting performance of the Al 2 O 3 -based shell to DZ125 superalloy.