Abstract: A novel Ti-6Al-3Mo alloy was prepared by laser multi-layer deposition from pure Ti,Al and Mo powders,and the microstructure and hardness distribution of the deposited layers were investigated.Firstly,the morphology of the prior-β grains and formation mechanism of the grain morphology were investigated combining with the columnar to equiaxed transition (CET) mechanism during solidification.It was found that the deposited layers are dominated by the large columnar grains growing epitaxially,and only some smaller sizes of equiaxed grains exist at the very top.Secondly,the microstructure in the prior grains was studied,and it was found that the microstructure of laser deposited Ti-6Al-3Mo is composed of some primary α laths,a large quantity of α colonies and the residual phase.Finally, the micro-hardness distribution of the deposited layers was tested.The work would lay a foundation for the further study and application of laser multi-layer deposition of Ti-6Al-3Mo alloy.