Objective To investigate the expression and clinical significance of early-stage serum interieukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) in patients with acute organophosphorus pesticide poisoning (AOPP). Method 186 cases of AOPP were divided into mild group, moderate group and severe group according to the severity. 30 healthy volunteers served as control group. APACHE Ⅱ scores were evaluated for these patiences and their serum concentrations of IL-10 and TNF-α were detected by enzyme-linked immunosorbent assay (ELISA). Results APACHE Ⅱ scores increased significantly with the exacerbations of AOPP (P ＜0. 05). The serum IL-10 concentrations of AOPP was slightly higher than the control group. There was no significant difference compared with the control group (P ＞0. 05). APACHE Ⅱ scores positively correlated with the serum TNF-α concentrations, but not with the serum IL-10. However,the ratio of TNF-α and IL-10 positively correlated with APACHE Ⅱ scores ( P ＜ 0. 01 ). Conclusions There were pro-inflammatory response and anti-inflammatory response in patients with AOPP. Overrelease of inflammation promoting factor and imbalance between inflammation promoting and inhibiting factors correlated with the severity of AOPP, which may be an important mechanism of multiple organ dysfunction syndrome of AOPP.