From the samples collecting from the duck hepatitis virus infected the ducklings in Ninh Thuan province in 2013, a virus strain was isolated and signed as the strain NT. The entire of code and gene sequence analysis of 2271 nucleotides of the gene section P2 consisting of 4 polyproteins, such as: 2A1, 2A2, 2B and 2C was identified. The gene section P2 of the duck hepatitis virus, the strain NT having the similar rate of nucleotide was 93-98 percent compared to the strains of DHAV-3, 80 percent compared to the strains of DHAV-2 and 74-77 percent compared to the strains of DHA V-1, particularly up to 98 percent compared to the Chinese strain B-N (GerlBank: JX235698) but only 93 percent compared to the Vietnamese strain DN2 isolated previously in Dong Nai province in 2009 (GenBank: JF914944). In comparison with the vaccine strain VXXT (DHAV-1 genotype) currently used in Viet Nam, the similar rate of the strain NT was only 74 percent (nucleotide) and 83 percent (amino acid). It is warned that there is a difference in the antigen - immunity compatibility of the hepatitis virus genotypes A in the duck population in Vietnam. Results derived from the phylogenetic analysis also confirmed that the strain NT of duck hepatitis virus A in Vietnam belongs to genotype 3, along with those strains of South Korea and China, especially the strain NT has the closest genetic relationships with the Chinese strain B-N.