In-situ observation of deformation in semi-solid alloys at the grain scale has been carried out using X-ray radiography. This paper characterizes the deformed microstructure in the semi-solid state by a quantitative analysis of solid motion from the image sequences obtained by the in-situ experiment on semi-solid Al-Cu alloys. A velocity of solid, a shear strain rate and a divergence of solid rate, which correspond to the change in solid fraction, were evaluated during a 0.5-1d (d: crystal size) increment of direct shear. The effect of solid morphology on the shear deformation was also examined by in-situ observation of deformation in water-polystyrene particle mixture where the polystyrene particles are spherical (shape factor~1) with diameter of 500 μm. The shear strain was localized in the vicinity of the shear domain and the localized area corresponds to the area where the solid fraction decreased both in semi-solid Al-Cu alloys and the water-particle mixture. The waterpolystyrene particle mixture showed a narrower localized area of the shear strain than that of Al-Cu alloys due to the difference in the solid shape.