Viral DNA of Taiwanese PCV2 was extracted and the ORF2-encoding region was amplified by PCR. The PCR product was inserted into the different vectors, and the expressed proteins in eukaryocytes were identified further with anti-PCV2 polyclonal antibody by Western blotting. Recombinant ORF2 protein will be purified with HisTrap column, and coated on the surface of 96-well ELISA plates. The antibodies titers of the sera from different farms and age groups will be determined by ELISA. We have designed different peptide-based antigen for PCV2 effective in swine. The peptide immunogen have various epitope from the ORF2 capsid protein of PCV2. The safe chemically-defined product would have considerable advantages for immuno-dot assays to detect antibody titers of serums.. On the other hand, real-time PCR will be applied to detect antigens of PCV2 in serums.