Abstract: AIM: To explore the protection of PR39 for acute myocardial ischemia and to construct the NT4-TAT-His-PR39 cDNA secreting and expressing PR39. METHODS: PR39 cDNA was obtained by PCR twice, which contained restriction enzyme sites on the two extremities. PR39 cDNA was connected with the signal peptide and leader peptide of neurotrophin 4 (NT4) cDNA, TAT cDNA, 6×His cDNA by molecular biological method. The NT4-TAT-His-PR39 was inserted into the plasmid of pBV220. RESULTS: The length of fusion gene was 421 bp, and restriction enzyme digestion confirmed that the gene expression box of NT4-TAT-His-PR39 was successfully constructed. DNA sequencing and DNAsis software analysis results indicated that NT4-TAT-His-PR39 gene sequence was completely consistent with that of the experimental design. CONCLUSION: The NT4-TAT-His-PR39 fusion gene is successfully constructed in this experiment, which secretes PR39, crosses cellular membrane, and contains a 6×His tag.