研究了激光焊接工艺参数（离焦量、激光输出功率、焊接速度等）对２０ＣｒＭｎＴｉ钢焊缝宏观形貌及其焊接接头组织的影响。通过金相组织分析、透射电镜观察以及硬度测试等研究结果表明，采用激光焊可以实现２０ＣｒＭｎＴｉ钢作为分体加工齿轮材料的深熔焊接，其热影响区较小，且可得到混合型马氏体组织。 The effects of laser welding process parameters (defocus amount, laser output power, welding speed and so on) on the macro-morphology and weld joint structure of 20CrMnTi steel were studied. The results of microstructure analysis, transmission electron microscope observation and hardness test show that 20CrMnTi steel can be used as the deep-penetration welding of split gear materials by laser welding, and its heat-affected zone is small, and the mixed martensite organization.