The invention provides a waste treatment system and a waste treatment method. The waste treatment system and the waste treatment method can be used for treating complex and dangerous wastes such as fly ash and sludge. The waste treatment system comprises a pretreatment system, a plasma sintering melting treatment system and a tail gas treatment system, wherein the pretreatment system is used for receiving a to-be-treated material and uniformly mixing the to-be-treated material with ingredients according to predetermined proportions to further form material particles with specific shapes; the plasma sintering melting treatment system carries out sintering melting treatment on formed material particles by using a plasma generator to obtain a glass ceramic body and exhausts flue gas treated in the sintering melting treatment process of the material particles into the tail gas treatment system. The tail gas treatment system receives the flue gas, carries out purification treatment on the received flue gas, and enables the flue gas to become exhaust gas according with exhaust standards. The waste treatment system and the waste treatment method provided by the invention can be used for treating the complex and dangerous wastes such as the fly ash and the sludge so as to effectively prevent the wastes from being diffused to the environment.