Kinetics of hydrogen absorption in TC4 alloy was studied by hydrogenation experiments at different temperatures and initial hydrogen pressures, and the effects of hydrogenation on the microstructure and phase composition of TC4 alloy at room temperature were studied. The results show that the reaction rate constant of TC4 alloy increases with the rise of hydrogenation temperature, and the time required for the reaction to reach equilibrium is gradually shortened. The apparent activation energy of hydrogen absorption reaction of TC4 alloy is 79.42 kJ/mol by solving the Arrhenius equation. δ hydride and α" martensite appear in the microstructure of hydrogenated TC4 alloy.