Objective:In this experiment,ELISA measurement was developed to detect antibody agaist PCV-2.Methods:A Cap sequence encoding for antigen epitope was obtained by PCR from the genome of porcine circovirus type 2 and then cloned into prokaryotic expression plasmids pET-22b(+).The plasmid of pET-22b(+)-cap was successfully constructed and transformed into E.coli BL21(DE3).An ELISA for detection of PCV-2 was established by high expression of Cap protein after induced by IPTG.Results:The results of Western blot showed that the expressed protein was 30 kD and possessed immunological activity.Positive rate was 73.1% and negative rate was 26.9% respectively for 643 serum samples which were examined with the measurement by ELISA.Conclusion:The ELISA method is applicable in clinic.