African swine fever (ASF) is a contagious viral disease in pigs, caused by the African swine fever virus (ASFV). Currently, there are no effective vaccines and drugs for ASFV, making diagnostic methods crucial for the prevention and control of ASF. In this study, the ASFV p30 protein was successfully expressed using a prokaryotic expression system and used as an immunogen to prepare monoclonal antibody (mAb) 2A5. The antigenic epitope recognized by the mAb 2A5 was identified as