This study proposes a gene therapy drug AAV‐OTOF and provides preclinical and systematic efficacy and safety evaluation for AAV‐OTOF gene therapy both in mice and nonhuman primate, and also establishes a hearing‐safe approach for AAV delivery into the inner ear in nonhuman primate, which can be used to guide the clinical studies of OTOF‐related deafness DFNB9 and provide methodological support for inner ear gene therapies. The gene discussed is OTOF; the disease is deafness.