The source water of Fusun Water Treatment Plant is from Cing-sheui and Nan-Gan channel. The efficiency of particle destabilization by coagulation can be significantly affected by the quality of source water. The raw water of Fusun Water Treatment Plant will be collected to perform the jar test every month. The performance of oxidation to Fe and Mn ions will be evaluated and the performance of turbidity removal and the residual Al of supernatant after coagulation-sedimentation process for natural water with different turbidity will be analyzed. Then, the supernatant will be filtered by membrane with a pore size of 0.45 µm. After that, the quality of filtrate will be determined to confirm if it complies with the limit of drinking water quality standard. Finally, the cure of optimum coagulant dosing for different raw water will be established.