Coagulation is popularly used in water treatment plants as pretreatment of filtration. The advantages of rich experiences and cost-efficiency also make it become one of the competitive pretreatment of membrane filtration. However, diverse coagulation conditions including the type, dose of coagulants and operating conditions (pH, temperature, flux) influence the performance of membrane filtration. The first objective of this study is to find out the optimal coagulation pretreatment condition by comparisons of three types of coagulants at different doses. The second objective of this study is to identify the sedimentation potential under different operating conditions. The third objective of this study is to evaluate effects of two different filtration modes, which include "pressured" mode and "submerged" mode, on membrane performance. The results imply that coagulant types have different effects on water quality improvement at different doses. The fouling is reduced at the under-dose and the maximum UV254 removal conditions. Sedimentation helped to improve the membrane performance. The submerged mode perform better than pressured mode under all conditions.