Objective To investigate the motor ability and skeletal muscle pathology in mice with Duch⁃ enne muscular dystrophy（DMD）and to explore the therapeutic effects of Deflazacort on DMD. Methods Ten ⁃ weeks⁃old transgenic DMD mice were selected and randomly divided into normal control group，model group and Deflazacort ⁃ treated group according to their body weights，seven in each group. The mice in all groups were weighed once a week for an experimental period of 8 weeks. At 10，14 and 18 weeks of age，the mice were assessed for locomotor activity by hanging test，pole climbing test and grip strength test，and at 18 weeks of age，the mice were observed for changes in limb stride distance，followed by testing their walking speeds by gait test. After eutha⁃ nasia，muscle lesions were assessed by measuring serum creatine kinase，lactate dehydrogenase，muscle pathology histology and morphological analysis. Results Compared to the DMD mice，there were no significant changes in body weight in Deflazacort ⁃treated mice，but the suspension time was prolonged（P < 0.05），the pole climbing elapsed time reduced（P < 0.01），the forelimb grip increased（P < 0.05），and the stride distance and walking speed both increased（P < 0.01）. Meanwhile，the serum creatine kinase values were lowered，and the areas of skeletal muscle inflammatory cell infiltration（P < 0.01）and fibrosis were reduced. Conclusion Deflazacort is effective in treating hypokinesia，gait bradykinesia and skeletal muscle inflammatory damage in mice with DMD.