Calf pneumonia apostematosa has increased in recent years and major pathogen was Arcanobacterium pyogenes by detecting. The purpose of this study is to develop a PCR method for Arcanobacterium pyogenes diagnosis. A pair of specific primer was designed and synthesized according to 16S rRNA of Arcanobacterium pyogenes. After PCR method was optimized, the specificity and sensitivity was assayed. The specific DNA fragment (927 bp) was successfully amplified with the following condition: 0.2 μmol/L optimal concentration of primer, 58°C anneal temperature and 1.5 mmol/L Mg2+ concentration. The specific test results showed that Arcanobacterium pyogenes could be amplified to obtain 927 bp, however the amplified results of Escherichia coli, Staphylococcus aureus, Bacillus pyocyaneus, Streptococcus pyogenes, Bacillus cereus, Salmonella, Klebsiella pneumoniae and Bacillus proteus were negative. The results of sensitivity test indicated that the minimum detection limits of PCR were 42 Arcanobacterium pyogenes. The PCR diagnosis method of bovine Arcanobacterium pyo-genes was successfully established and this method has high specificity and sensitivity. This research provides new means for the rapid diagnosis of the bovine purulent pneumonia and epidemiological in-vestigations.