提出了钢浸润硬质合金的激光焊接机理。讨论了激光焊接过程中ＷＣ和Ｃｏ的状态变化，分析了焊缝结构和成分变化对焊接质量的影响，给出了试件的无裂纹的冶金焊接结果。 The laser welding mechanism of steel infiltrated cemented carbide was proposed. The change of state of WC and Co during laser welding was discussed. The influence of weld structure and composition variation on welding quality was analyzed. The crack-free metallurgical welding result of the specimen was given.