Abstract: The indirect hemagglutination assays was obtained by sensitization of sheep red blood cell with the separated and purifitied capsular polysaccharide (CPS) of Actinobacillus pleuropneumoniae serotype 3. The result showed that the speciality of the indirect hemagglutination assays was good. It could only agglutinate the same type positive antibody and could be used to detect Actinobacillus pleuropneumoniae serotype 3 antibody. Simple fast economic way to test Actinobacillus pleuropneumoniae antibody with the indirect hemagglutination assays. It is a valid means to diagnose and prevent Actinobacillus pleuropneumoniae.

Key words: Actinobacillus pleuropneumoniae; capsular polysaccharide; indirect haemagglutination assays