Objective：To study the value of Creactive protein (CRP) and interleukin6(IL6) in the diagnosis of acute pancreatitis (AP) associated with infection. Methods：Sixty SD rats were randomly assigned into group AP (n=40) and shamoperation group (S, n=20). Plasma CRP and IL6 were detected before AP(0h), and at 12h, 24h and 48h after AP. Serum amylase detection and ascitic bacteria culture were carried out at 48h. Results：（1）In AP group, 36 rats were alive. Ascitic infection developed in 16 cases (group AP1), and not in the other 20 cases (group AP2). （2）Plasma CRP and IL6 levels in group AP1 and AP2 were significantly higher than those in group S (all, P<0.01). In group AP1, compared to group AP2, except the CRP concentrations at 48h had a significant increase(P<0.01), at all the other time periods, no significant differences of plasma IL6 and CRP concentrations were observed (all, P>0.05). (3)In group AP1, IL6 and CRP elevated significantly at all time periods after the model setup (P<0.05). But in group AP2, elevation of IL6 and CRP was only observed at 12h(both, P<0.05), and there was no significant difference between 24h and 48h (P>0.05). Conclusions：Plasma CRP has predictive value in the diagnosis of early infection in acute pancreatitis, but plasma IL6 is not sensitive to secondary bacteria infection in acute pancreatitis.