Abstract: OBJECTIVE To observe the changes of the levels of serum PCT, TNF-α, CRP and IL-6 in patients with surgical peritoneal cavity infections, and their correlation with the degree of infections, so as to provide evidence for guiding antibiotics application. METHODS A total of 69 patients with surgery peritoneal cavity infections and 24 patients without peritoneal cavity infection treated in general surgery department in our hospital from Nov. 2012 to Dec. 2016 were enrolled. According to the difference of scope of peritoneal cavity infections, they were divided into non-infected group (24 cases), local peritoneal cavity infection group (38 cases) and diffuse peritoneal cavity infection group (31 cases). The levels of temperature (T), WBC, N%, serum PCT, TNF-α,CRP and IL-6 were detected on admission and the third day after anti-infective therapy, and the correlation between PCT, TNF-α,CRP, IL-6 and WBC were analyzed. RESULTS The levels of T, WBC, N%, CRP, TNF-α and IL-6 on admission in diffuse peritoneal cavity infection group and local peritoneal cavity infection group were significantly higher than those in non-infected group (P＜0.05), and the levels of TNF-α and IL-6 in diffuse peritoneal cavity infection group were higher than those in local infection group. Compared with local infection group and non-infected group, the level of PCT in diffuse infection group was significantly higher. On the third day after the anti-infective therapy, the levels of T, WBC, N%, CRP, TNF-α, PCT and IL-6 in the two infection groups decreased significantly, compared with the levels on admission (P＜0.05), while the levels of TNF-α, PCT and IL-6 in diffuse peritoneal cavity infection group were still higher than that those in local peritoneal cavity infection group. The expression of PCT, TNF-α, CRP and IL-6 were all positivele correlated with WBC. CONCLUSION Clinical detection of serum PCT, TNF-α, CRP and IL-6 is benefit to distinguish whether or not the surgery peritoneal cavity infection exists. Compared with CRP and WBC, the detection of PCT, TNF-α and IL-6 is more benefit to evaluate the severity of peritoneal cavity infection, and also has certain guiding significance to the application of antibacterial drugs.