A novel Ti-6Al-6Mo alloy sample was fabricated by laser solid forming (LSF) using blended elemental powders as raw material. The microstructure of as-deposited sample and the effects of solution and aging treatment on the microstructure and microhardness of LSF Ti-6Al-6Mo alloy were discussed. The results showed that the heat treatment conducted in this study has no significant effect on the morphologies of prior b grains of the alloy. The solution temperature, solution time, and the cooling method after solution treatment have a significant effect on the morphology and size of the α phase in the prior β grains and the microhardness of the LSF Ti-6Al-6Mo alloy. When the aging time exceeds 4 hours, the microstructure and microhardness of the alloy change little with increasing aging time. Based on the analysis of precipitation and strengthening effect of the primary α laths and secondary α laths on the b matrix in LSF Ti-6Al-6Mo alloy under different heat treatment conditions, the influence mechanism of heat treatment on the microstructure and microhardness of LSF Ti-6Al-6Mo was revealed.