Once a cat is diagnosed with FIP, the cat usually dies within a few days to weeks. Therefore, a clear diagnosis is essential. However, the diagnosis of FIP is actually very complex and difficult. We need to comprehensively consider the cat's life background, medical history, clinical signs, laboratory examination, antibody titer, etc., so as to evaluate the possibility of FIP, but we can't make final confirmation. At present, pet hospitals do not have a good diagnostic method for feline infectious peritonitis. It mainly depends on laboratory diagnosis (blood routine, blood biochemistry, ascites Biochemistry) and imaging analysis. Among them, albumin, globulin and PCR are particularly important. Although many FIP cats have characteristic CBCS, albumin and globulin levels and a:g, not every cat will fully meet the above parameters, which still needs to be considered in combination with age, origin, clinical signs and physical examination. The results are considered comprehensively. If these common abnormalities are generally consistent with clinical symptoms, it can be reasonably diagnosed as feline infectious peritonitis.