提高扫描速度可使Ｃｏ基合金经激光表面重熔处理后显微组织明显细化。通过定量金相法测定枝晶二次臂间距查明，扫描速度提高一个数量级，熔池中部的二次臂间距减小一半。依据传统的凝固理论，结合激光重熔三维流场和温度场模型计算出的冷却速率和ＣｏＣｒＣＷ伪二元相图，计算出不同扫描速度下熔池中部的二次臂间距，计算结果和实验结果符合得很好，成功地从理论上解释了实验结果，建立了激光重熔的工艺和组织特征之间的联系。 Increasing the scanning speed can make the Co-based alloy remarkably refine the microstructure after laser surface remelting. Determined by the quantitative metallographic determination of dendrite secondary arm spacing identified, the scanning speed increased by an order of magnitude, the middle of the weld pool in the secondary arm spacing reduced by half. According to the traditional solidification theory, combined with the cooling rate and CoCrCW pseudo-binary phase diagram calculated by laser remelting three-dimensional flow field and temperature field model, the secondary arm spacing , The calculated results are in good agreement with the experimental results. The experimental results are successfully explained theoretically, and the connection between the process and organizational characteristics of laser remelting is established.