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Conventional reverse genetics for classical swine fever virus(CSFV)is based on the transfection ofpennissive cells with either in vitro．Or intracellularly-synthesized RNA transcripts from a viral genomic eDNA clone·Thesestrategies are complicated，inefficient and time—consuming．This study is aimed to develop an improved reverse genetlcsmethod for me direct．Rapid and efficient recovery of CSFV from cloned eDNA．The eDNA clone，pBRCISM，wasconstructed．Which harbors the full．1ength genomic sequence from the CSFV Shimen strain flanked by the cytomegaloviruspromoter(an RNA polymerase II)，a chimeric intron and hammerhead ribozyme sequences at the 5。End，and the hepatitisdelta vims ribozyme and SV40 polyadenylation signal sequences at the 3-end．Infectious progeny virus was rescued fromPK-15 cells directly transfected with pBRCISM and its morphology and one—step growth characteristic were indistinguishablefrom the parent virus and virus rescued from classical reverse genetics．The reverse genetics method based on RNAoolymerase II yielded a 120．Fold increase in the titer of nascent virus in less time(12 h less)than a reverse genetics methodbased on in vitro transcription．The improved reverse genetics method developed in the present study is efficient，convenientand cost．Effective，and will be valuable for the rapid recovery of CSFV mutants．