In the present study, magnetic and magnetostrictive properties of Tb(Fe 1 - x Mn x ) 2 compounds were examined by magnetic measurement, Mossbauer and X-ray study. The Mossbauer study shows that the easy magnetization direction of the compounds may deviate slightly from the major axis of symmetry; and the average isomer shift of the compounds increases with increasing x-value, which was attributed to the charge transfer from 3d electrons of Mn atoms into the 3d band of Fe. It was also found from the X-ray measurement that the spontaneous magnetostriction λ 1 1 1 decreased due to Mn substitution, which can be understood on the basis of the single-ion model. The increase of the polycrystal magnetostriction λ s due to Mn substitution was also found and can be ascribed to the increase of λ 1 0 0 , which was suggested to be caused by the change in the filling of d-bands due to substitution.