Nickel was continuously plated via magnetron sputtering and electroplating on the surface of Ta-based alloy processed by micro-arc oxidation, and its effects on the thermal shock resistance of the ceramic scale formed on the surface of Ta-based alloy to molten nickel was investigated. The results showed that the ceramic scale with a thickness of 30~35μm prepared by micro-arc oxidation was mainly Ta₂O₅. Although the ceramic layer was continuous and bonded well to the alloy substrate, severe cracking and peeling occurred when it contacted with the molten nickel during casting, which caused the melting of the Ta-based alloy. Fortunately, the thermal shock resistance of the ceramic scale to molten nickel was greatly improved by the plated nickel layer with a thickness of 20~30μm. The ceramic scale was still continuous and integrity after nickel casting. Thus, the nickel plating can be used as a protection coating for the ceramic scales on the Ta-based alloy prepared by micro-arc oxidation in molten nickel environments.