In order to get a better understanding on the hydrogen-deformation interactions on the recrystallization of titanium alloys, solution-annealed and cold-rolled β-21S titanium samples were electrolytically charged with hydrogen under various charging conditions. It was observed that the lattice parameter of cubic body centered the βp-phase increased proportionally to the charging time without any formation of hydride while the charging current density appeared to have no significant effect on the variation of the lattice parameter. However our results indicated that the pre-plastic deformation (cold rolling) enhanced the hydrogen absorption capacity in the specimens. The effects of hydrogen on the plastic-deformation and recrystallization of β-21S titanium alloy has been investigated by a systematic analysis of the microstructures by means of X-ray diffraction and SEM coupled with Electron Back-Scatter Diffraction.