利用Ｘ射线衍射法对Ｗ１８Ｃｒ４Ｖ高速钢激光相变强化层的残余应力进行了测定和分析。试验结果表明，相变强化层表面的残余应力为压应力，内部为拉应力，近似按正弦函数分布。其大小和分布状态随工艺参数的变化而改变。当改变工艺参数使表面熔化时，表面为拉应力 The residual stress of laser phase transformation strengthened layer of W18Cr4V high speed steel was measured and analyzed by X-ray diffraction. The experimental results show that the residual stress on the surface of the phase-change strengthened layer is compressive stress and the internal is tensile stress, which is approximately distributed according to the sine function. The size and distribution of the state changes with the process parameters change. When changing the process parameters to melt the surface, the surface is tensile stress