• The Participants and/or his legal guardian must fully understand the purpose, nature, methods, and potential risks of the study, and sign a written informed consent form.

• Ambulatory male subjects aged 4 years and above but under 9 years (4 years ≤ age \< 9 years).

• Any mutation in the DMD gene confirmed by genetic testing

• Serum creatine kinase (CK) during the screening period meets the study requirements.

• Receiving stable, standard-dose glucocorticoids before screening.

• The subject's AAV capsid antibodies meet the clinical trial requirements.

• Able to cooperate with motor function assessment, MRI, and muscle biopsy as required by the study.

• Laboratory test results during the screening period and at baseline meet the standards.

• The subject and/or his legal guardian must fully understand the study procedures, be willing to actively cooperate, commit to high compliance with the protocol, and ensure that the subject attends all scheduled visits.