Currently available gene therapies for hemophilia include CRISPR-Cas9 gene editing technology, retroviral vectors, and recombinant adenovirus-based gene therapy for hemophilia. 1. CRISPR-Cas9 gene editing technology has now demonstrated good efficacy in the treatment of diseases such as sickle cell disease and β-thalassemia, but its use in hemophilia is still under attack. Although it is not easy to correct inverted faulty genes, some studies have shown that this method can restore the expression and function of FVIII or FIX in hemophilia A and B mice. 2. Retroviral vectors, transfect human F9 gene into patients’ isolated skin fibroblasts, screen for FIX-expressing cells, and after a series of safety tests embedded in collagen and injected into patients’ subcutaneous tissues in the abdomen or back. Early hemophilia gene therapy used viral (e.g., adenoviral vectors) and non-viral vectors, which had a reasonable safety profile but did not achieve sustained transgene expression at the therapeutic level. 3. Hemophilia gene therapy based on recombinant adeno-associated virus (rAAV). rAAV is derived from wild-type AAV, which is the most promising in vivo gene therapy vector for hemophilia because of its high safety profile, wide range of host applications, and long in vivo expression time. However, it has not yet been utilized in the clinic. The above is the basic introduction of hemophilia gene therapy, and it is recommended that patients should have early detection, early diagnosis and early treatment, and carry out the treatment in an orderly manner under the guidance of professional physicians in order to achieve the best therapeutic effect.