1. Study population:It is applicable to male participants with genetically confirmed and clinically confirmed Duchenne muscular dystrophy (DMD), aged between 6 and 10 years.
2. Research period:The main research period of this clinical study is one year. Participants were tested during the baseline period and were followed up on days 0, 7, 14, 21, 60, 120, 200, and 360.
3. Exploratory indicators：MR Of both thighs, quantitatively calculating the muscle fat replacement indicators of the buttocks and proximal thighs；Patient Self-Rating Scale, Caregiver Self-Rating Scale.
4. Safety assessment：The safety assessment population will include all participants who have received the drug dose and have at least one post-drug safety assessment. Adverse events (AE) collected from the participants signed informed consent, all the way to the main study period at the end of the last follow-up. Safety laboratory evaluation, laboratory safety monitoring, including hematology, blood biochemistry, urine analysis (including troponin I, CK and CK - MB) and blood coagulation function, as well as complement. All common medication will be recorded. All adverse events, including abnormal complete blood cell count results, will be continuously tracked until they are resolved or stabilized. Only treatment-related adverse events (TEAE) will be summarized. AEs will be based on MedDRA and organ systems are recorded and archived. The classification and terminology related to AEs will be described according to the version of CTCAE v6.0.

Inclusion Criteria:

1. Participant age: 6-10 years old (including 10 years old).
2. Gender: male.
3. Gene diagnosis of DMD gene type, conform to the DMD phenotypes and clinical manifestations.
4. There has been a muscle weakness, symptoms of motor function decline.
5. Patients could walk independently, able to complete 10 meters walk test. Lie on your back up,
6. patients can complete independently and got up time is less than 30 seconds.
7. Participants cognitive assessment and mental state can cooperate movement.
8. Never accept oral hormone therapy or stop using hormone therapy more than six months.
9. Willing to accept and be able to cooperate with more than one muscle biopsies.

Exclusion Criteria:

1. The participants are in active virus infection or other pathogen infection, including but not limited to, the TORCH virus, Epstein - Barr virus, the new crown virus, bacteria, fungi, etc.
2. Having received a live attenuated vaccine or systemic antiviral, anti-infective and/or interferon therapy within 3 months prior to the treatment with investigational product.
3. Serological tests revealed infections of HIV, HBV, HCV and syphilis.
4. Severe infections (such as pneumonia, pyelonephritis or meningitis) occurred within 8 weeks before the start of treatment with investigational product.
5. There are clear symptoms of cardiomyopathy, and echocardiography shows that the left ventricular ejection fraction is less than 50%.
6. Continuous or intermittent assistance support from a ventilator is required.
7. Laboratory biochemical tests the following indices abnormal: gamma GGTP (gamma glutamyl transpeptidase) 2 times higher than upper limit (GGT), total bilirubin is higher than 1.5 times the upper limit of the elf inhibition C (cystatin C) > 1.27 mg/L, hemoglobin (Hgb) < 100 g/L or > 200 g/L; White blood cell (WBC) <4×109/L or >18.5×109/L or platelet ≤125×109/L.
8. The patient has received any type of gene therapy (such as AAV gene therapy), cell therapy (such as stem cell transplantation), in vivo editing or in vitro editing reinfusion gene editing therapy (such as CRISPR-Cas9, TALEN), or other experimental drug treatments in the past.
9. Participants have any taboos on immunosuppressive therapy.
10. Other comorbid diseases or conditions that the principal investigators considered unsuitable for participation in clinical trials.
11. The families of the participants do not wish to publicly disclose the patients' research participation to the attending physician and other medical providers.