Анотация: In order to investigate the epidemiology of classical swine fever virus (CSFV) in China, the E2 glycoprotein gene of 68 CSFVТs (domestic pigs) was isolated from mainland China during 1982-2009 and aligned, and a phylogenetic tree was constructed by the neighbor-joining (NJ) method using Phylip software package (version 3.68). Phylogenetic analysis of 190 nucleotides (nt) (located in 2518-2707) from E2 gene showed that 23 isolates were classified into roup 1 (subgroup 1.1) and 45 isolates were divided into Group 2, with 36 isolates being clustered into subgroup 2.1, subgroup 2.2 (8 isolates) and subgroup 2.3 (1 isolate). The results indicated that both CSFV Group 1 and Group 2 contributed to the epizootic of classical swine fever (CSF) in mainland China. Subgroup 2.1 virus population was more predominant in the economically developed southeast China along the coast whereas subgroup 1.1 mainly caused epizootics in inner provincial areas. Epidemiologic regional specificity might be caused by immune selection pressure between the two groups of CSFV