Abstract: Pre-oxidation and coagulation sedimentation process is proposed to treat the micro-polluted water in a reservoir in Southern Jiangxi considering the shortcomings of the conventional coagulation process. Using potassium permanganate as oxidant, we examine the effects of potassium permanganate preoxidation on the micro-polluted water treated by coagulation sedimentation. The results show that with the conditions of coagulation stirring intensity 260 r/min for 2 min, flocculation mixing intensity 80 r/min for 25 min, PAC dosage of 10 mg/L, the optimum pre-oxidation condition is that when pre-oxidation dosing point is 2 min earlier than coagulant dosing, potassium permanganate dosage is 1.0 mg/L, and pH value is 8. After the polluted water is treated by pre-oxidation and coagulation, the turbidity, COD_Mn, UV₂₅₄, ammonia nitrogen, iron and manganese removal rates are 99.02 %, 68.78 %, 50.94 %, 33.96 %, 96.77 %, 81.67 % respectively. The effluent can meet the National Drinking Water Health Standards.