Abstract: B₄C coating can provide low Z and stable refractory surface.B₄C coating with the thickness of 200 300 μm was processed by vacuum plasma spray（VPS） on the substrates of stainless steel and copper alloy,which is an econmical and more efficient technology.By optimizing the spraying parameters of B₄C deposit,a satisfactorily thermal shock resistance was obtained under the controlled temperature and atmosphere,which is suitable for plasma erosion protective purposes in nuclear fusion device.