Indirect immunofluorescence assay (IFA) for detecting antibody of Porcine sapelovirus (PSV) from porcine serum was established by employed the strain PSV HuN1 cultured in PK–15 cells as antigen coating in plate. The primary antibody and fluorescent secondary antibody in the test were diluted to 300 times. The results showed that the approach not only had high specificity and sensitivity which could discriminate PSV from other porcine virus antigens (such as PRRSV, FMDV, PCV, and CSFV), but also could detect positive serum sample with concentration low to 0.128 SN titer. The fact detected by the established method that 68% samples out of 208 serums from commercial farms scattered in Hunan province were positive indicated that the PSV was widely prevalent in the region, and the infection was mainly occurred in the weaning period.