The invention provides an E2 recombinant protein. The E2 recombinant protein has an amino acid sequence of a sequence table SEQ.ID.No.1, and the E2 recombinant protein has a base sequence of a sequence table SEQ.ID.No.2. The invention also provides application to an indirect ELISA kit for detecting bovine viral diarrhea virus antibodies. The E2 recombinant protein provided by the invention has high accuracy, not only is the neutrality of the protein ensured, but also the trouble of high mutation rate is avoided, and the recombinant protein is more beneficial to the development of a BVDV antibody detection technology. The E2 recombinant protein uses a traditional protein prokaryotic expression technology, the cost is low, the expression quantity is large, and after the successfully expressed E2 recombinant protein is subjected to urea gradient renaturation, the West blot detection reactionogenicity is strong. The E2 recombinant protein is applied to the indirect ELISA kit for detectingbovine viral diarrhea virus antibodies, and an established BVDV antibody ELISA detection method is high in sensitivity and good in specificity, is more beneficial to popularization and application ingrass-roots farmers, and is more beneficial to purification of BVDV in cattle herds in China.