In this work，the microscopic defects in Ti-Mo alloy hydrides were studied by using small-angle X-ray scattering (SAXS) technique. The results show that the SAXS intensity measured for hydride of 5at％ Mo alloy was lower than that of other hydrides in the high scattering angle range. The crystal grains and its internal sub-structures in the hydrides are the scatterers which cause SAXS. The sub-structures are induced by the large number of dislocations in the hydrides produced during hydrogenation. The crystal structure of Mo 5at％ alloy is mainly hcp，but that of the other alloys is bcc. The hydrides of all these alloys, however, have a fcc crystal structure. Therefore，it is indicated that the Ti-Mo alloys with hcp and bcc crystal structures form the same hydride structure，but induce different types of dislocation defects during hydrogenation.