A resolution V 2^10-3 fractional factorial design method was estimated to identify the main effect and second-order effects of pesticides and heavy metals concentrations in a composite contamination system on adsorption of sediment to metalaxyl, combined with a fixed effects model. It was found that contributions of the second-order interaction effects of the pollutant factor concentrations (79%) was dominated in controlling metalaxyl adsorption to sediment in the system than that of the main effect (21%), and the significant synergistic and antagonistic effects to metalaxyl adsorption were 47.93% and 52.07%, respectively, indicating that metalaxyl adsorption was inhibited. Meanwhile, the main effect and second-order effects of the pollutant factor concentrations (36.32% and 63.68%) in the synergies effects and (6.81% and 93.19%) in the antagonistic effects were calculated, showing that more contribution was attributed from the second-order effects of pollutant factor concentrations to metalaxyl adsorption in the combined pesticide and heavy metal system.