First-principle calculation was carried out on the Ti of hcp structure and Ti-H system supercells by a total-energy plane-wave ultrasoft pseudopotential method based on density functional theory (DFT), which combined generalized gradient approximation(GGA). Lattice parameters, total energy, energy band structure, density of states (DOS) and Mulliken population of the system were obtained. The calculated results reveal that after H atom introduction into the crystal cell of Ti8, Ti16 and Ti32, the formation energy of crystal impurity was decreased and the volume of crystal cell was swollen; the distortion would become serious and the volume would be increased obviously along with increase of the hydrogen concentration in the crystal cell. The intensity of the great mass of Ti-Ti bonds were enhanced in the octahedron storing H atom of crystal cell. The Femi energy level moved to the direction of low energy of DOS. The activity of Ti alloys was improved, and the transferred electrons were mainly those on the P orbit of Ti.