Abstract: Objective To assess the prognostic effect of the change of hemiplegic limb hardness by using elastosonography in spastic hemiplegia patients. Methods The strain of vastus lateralis, vastus medialis, rectus femoris and biceps femoris in healthy subjects of control group (n=20) and spastic hemiplegia patients of observer group (n=20) before and after the rehabilitation treatment in Taizhou Hospital of Zhejiang Province from July, 2013 to December, 2015 were observed by elastosonography. The influence of the changes of the muscles strain of spastic lower limb after 4 weeks of rehabilitation treatment on the prognosis of patients were evaluated. Results Before the treatment, there was statistically difference in the longitudinal strain between the normal limbs and spastic limbs in the observation group (P < 0. 01), and the longitudinal strain of vastus lateralis, vastus medialis, rectus femoris and biceps femoris of spastic limbs in the observation group were significantly higher than those in the control group (P < 0. 01). After the treatment for 4 weeks, the longitudinal strain of vastus lateralis, vastus medialis, rectus femoris and biceps femoris of spastic limbs at knee flexion was decreased significantly in the observation group (P < 0. 05). When compared with the control group, the longitudinal strain of vastus lateralis, vastus medialis and rectus femoris of spastic limbs decreased (P < 0. 05), but not of biceps femoris (P > 0. 05). At knee extension, the strain ratio of vastus lateralis, vastus medialis and rectus femoris of spastic limbs was lower than that of normal limbs and the control group (P < 0. 05), but the difference between biceps femoris of spastic limbs and the control was not significant (P > 0. 05). Conclusion The elastosonography can qualitatively detect the changes of muscle strain of spastic limbs in stroke patients with spastic hemiplegia, which can be used as the rehabilitation evaluation method for the prognosis of spastic hemiplegia patients.