The invention provides a vacuum sputtering device. A buffering piece is arranged at the edge of a back plate; the hardness of the buffering piece is lower than the hardness of a ceramic ring; the lower end of the buffering piece is fixedly arranged on a sputtering cavity installation plate; the upper end of the buffering piece is arranged between the upper surface of the ceramic ring and the upper surface of the back plate, so that the lower surface of the back plate is in contact with the top surface of the buffering piece before wearing the upper surface of the ceramic ring, and the ceramic ring is protected, a device sealing mode is ensured, simultaneously the cost generated when Teflon screws are arranged on the back plate, each target is required to be additionally machined in the prior art is saved, and the condition that the working accuracy requirements on a gasket is high when a Teflon gasket is placed between the back plate and the ceramic ring in the prior art can be avoided.