Abstract: Based on E2 gene sequences of CSFV Shimen published on NCBI, a pair of primers were designed and synthesized for detecting E2 gene. E2 gene was amplified by one step RT-PCR from total RNA, which had been extracted from tissues of pigs doubting infected by classical swine fever virus and PK-15 infected by CSFV F114. We compared IF method with one step RT-PCR which had been established. 24 samples of 26 samples doubting infected by CSFV were positive deteced by one step RT-PCR, the positive rate of one step RT-PCR was 92.3%. Results showed that the RT-PCR is specific and sensitive, and can be used as a method to identify CSFV isolates，detect samples of clinical cases and investigate molecular epidemiology of CSFV．

Key words: CSFV; one step RT-PCR; detection