The present invention discloses a strain of a recombinant 
cell line for stably expressing 
classical swine fever virus E2 
protein, and applications of the recombinant 
cell line in preparation of 
subunit vaccines and diagnosis reagents of 
classical swine fever, wherein specifically the recombinant 
cell line is BCSFV-E2, is preserved in the China General 
Microbiological Culture Collection Center, and has the preservation number of CGMCC No.7719. The 
classical swine fever subunit vaccine prepared by using the recombinant cell line has characteristics of high safety, good immunization effect, easy 
mass production, less being susceptible to exogenous 
virus pollution or influence of antibodies, and no influence of the 
maternal antibody on immunization of swine, and can induce and produce high level classical 
swine fever virus neutralization antibodies after the swine is immunized. In addition, the present invention further discloses a method for constructing the recombinant 
mammalian cell line, a method for preparing the classical swine fever 
subunit vaccine, and applications of the 
antigen expressed by the recombinant cell line in preparation of classical swine fever prevention vaccines and diagnosis reagents.