Micro-fine lightweight Nb-Ti based alloy powder was fabricated by hydride-dehydride method, and the hydrogen absorption/desorption behavior was investigated. The obvious hydrogen absorption occurs at 300 oC, and the absorbed hydrogen quantity reaches a saturation value of 1.12 wt.% at 400 oC. Binary and ternary hydrides (Nb0.803V0.197H, Nb0.696V0.304H and TiHx) were formed after hydrogenation. Hydrogen-induced embrittlement facilitates the pulverization of the thin alloy plate. During dehydrogenation process, hydrogen content was effectively reduced to 0.001 wt.% at 300 oC. Phase transformation from niobium or titanium hydrides to single phase solid solution alloy (β phase) was achieved. Oxygen content of the powder increases with increasing hydrogenation or dehydrogenation temperature due to the high reactivity of constituent elements with oxygen, both hydrogenation and dehydrogenation temperature of 400 oC is selected in order to prevent severe oxygen intake. Micro-fine Nb-based alloy powder with average particle size of 16 μm and oxygen content of 2980 ppm was obtained. Superfacial contamination of the obtained powder is detected, and oxygen impurity exists in the form of Nb2O5 and TiO2.