Ti-3wt.%Nb(αtype), Ti-20wt.%Nb(α+β,type) and Ti-40wt.%Nb(βtype) alloys were melted by vacuum are remelting. The specimens were homogenized at 1050℃ for 24 hr and were then hot rolled to 50% reduction. Each alloys were solution heat treated at β zone and α+β, zone after homogenization, and then aged. The microstructural and hardness changes in Ti-Nb alloys with Nb contents were investigated by SEM, XRD and hardness tester. The microstructural change from equiaxied to acicular and the increase of β phase in Ti-Nb alloys were obtained when the Nb content increased. The higher hardness value of α+βtype alloy was obtained compared to the other alloys.