Objective: To investigate the mutation of DMD gene in children， the dynamic of serum CK and transaminase and the correlation between the two enzymes of DMD， DMD muscle pathology, and the correlation with the age.Methods: 177 boys with DMD were prospectively studied. Results: ⑴By MLPA assay, the deletion mutation was account for 71.17% of DMD and the duplication mutations was account for 10.43%, no gene mutations had been detected in 18.40%. Of 30 children whose gene mutations was not been found, 10 were found DMD gene point mutations with next-generation sequencing technology. （2) The CK, AST, ALT activity in infants with DMD were significantly increased more than the normal 10,7,5 times respectively, and were maintained until the age of 8, then gradually declined with age increasing. Enzymes showed a linear correlation between CK and AST（r=0.817，p﹤0.01）or CK and ALT（r=0.669，p﹤0.01）levels. ⑶during the infant period of DMD, there were pathological changes, mainly as atrophy and hypertrophy of muscle fibers.  At the late stage, there was little number of muscle fibers, fatty connective tissue proliferation. The elder the more serious. Conclusion: ⑴The deletion mutation of DMD gene is the main type of gene mutation. ⑵Serum CK, AST, ALT level can reflect the DMD occurrences and progress, and provide an important basis for the early diagnosis of DMD. ⑶The severity of clinical illness and pathological changes is associated with the course of the disease and the age of muscle biopsy.