Objective To study the relationship between CRP and ascites due to cirrhosis complicated with infection. Methods One hundred and sixty-two cases of ascites due to cirrhosis complicated with infection were detected CRP with lactoprene coagulant glass test method and compared the results before and after treatment. Results In the patients with ascites due to cirrhosis complicated with infection,CRP was higher than that without infection (P0.05). Senitivity of CRP was higher than that of the temperature and differential white blood count (P0.05). Conclusion CRP is a sensitive mark to diagnose infection in the early stage of the patient with ascites due to cirrhosis complicated with infection.