Organic matter is abundant in the slight-polluted waters and in many ways affects the unit operations in water purification. Many studies showed that high molecular weight(HMW) organic matter was clearly easier to be removed in enhanced coagulation and clarification than low molecular weight(LMW) one, particularly the fraction with a molecular weight exceeding 500 Dalton(Da)，but the LMW organic substance could be easily degraded by microbes. Because the potassium permanganate (KMnO4) has strong oxidation, it can oxidize the HMW into LMW organic matter. The microbes on suspending plastic fillers can eat away the LWM organic matter. So we make use of the conjunction of suspending plastic filler and KMnO4, combining action of enhanced coagulation and biodegradation, to purify the slight-polluted drinking waters. In the study,under the controlled conditions of the experiment, it demonstrated that the conjunction could effectively remove turbidity, CODMn, NH3-N and UV254, the corresponding removal percent reached 88.60%、67.14%、65.00% and 40.00%.