Objective To explore the changes and effect of plasma renin-angiotensin system (RAS) and nitric oxide (NO) in rabbits pericarditis. Methods Twenty-one male rabbits were divided into two groups randomly. Experimental group: 11 rabbits were injected 40% urea (2ml/kg) into pericardial cavity, control group: 10 rabbits were injected 0.9% natrium chloride into the pericardial cavity . The concentration of plasma renin active (RA), angiotensin Ⅱ(ANGⅡ) and NO were measured before operation and after operation 1,4,7,10,15,21 days. The histopathological changes of pericardium, myocardium, lung and liver were observed in the adopted specimens. Results The concentration of plasma RA, ANGⅡ and NO in experimental group increased after operation and significantly increased at 7 to 21 day compared with those in control group (Plt;0.01). In the experimental group, there were proliferation and thickening of pericardium, myocardial degeration, pulmonary ecchymosis and hepatic ecchymosis. Conclusion The concentration of plasma RAS and NO is increased in rabbits with pericarditis, plasma NO rejects the roles of RAS, NO and RAS lead to organs injury of pericardium, myocardium, lung, liver and so on.