This research applied Cr₂O₃ coating on the surface of silicon-based ceramic core through multi-arc ion plating method. The effect of Cr₂O₃ coating on wetting behavior and interface reaction behavior of silicon-based ceramic core and nickel-based single crystal superalloy after contact at 1550 ℃ were studied using high-temperature in-situ droplet method. The interface morphology, element distribution, and reaction products after the interface reaction were analyzed using SEM, EDS, and XRD. The results show that the wetting angle between nickel-based single crystal superalloy and silicon-based ceramic core coated with Cr₂O₃ is 98.29°. Hf and Al in superalloy melt react with Cr₂O₃ coating, generating HfO₂, Al₂O₃, and free Cr at the bottom of superalloy. The generated Al₂O₃ forms a protective layer to prevent the diffusion of active elements in superalloy to the interface. However, a small amount of superalloy melt still reacts with the silicon-based ceramic substrate without coating protection, generating Al₂O₃ and free Si at the interface. The generated Cr and Si are enriched at the interface and form CrSi₂ on the superalloy surface. Part of Si diffuses from the surface of the superalloy to the interior, forming (Mo,W,Re)₅Si₃ with refractory elements such as W near the surface of superalloy. The results indicate that the wetting angle of nickel-based single crystal superalloy on silicon-based ceramic core coated with Cr₂O₃ is smaller than that on unmodified silicon-based ceramic cores, and its wettability is better. Based on the above analyses, the Cr₂O₃ coating on the surface of silicon-based cores is beneficial to improve the filling of alloy at local positions of castings, but its control effect on interface reactions is limited.