Abstract: Through the plasma spraying technology and the cold spraying high-speed deposition technology, an evenly distributed protective coating is formed on the surface of a plasma etching chamber. The protective coating, having a double-layer composite structure, includes a metal+Y2O3 coating as a metal+Y2O3 transition layer deposited by plasma spraying as a lower layer of the double-layer composite structure, and a high-purity Y2O3 ceramic coating coated on the metal+Y2O3 transition layer as an upper layer of the double-layer composite structure, the metal+Y2O3 transition layer is configured to reduce the difference in expansion coefficient between the Y2O3 ceramic coating and the metal substrate, and enhance the bonding force between the Y2O3 ceramic coating and the metal substrate; the high-purity Y2O3 ceramic coating is formed by depositing Y2O3 ceramic powders on the metal+Y2O3 transition layer at high speed through cold spraying high-speed deposition.