Abstract: Proposed are a method and a system for separating a cathode material of a waste lithium secondary battery using an oxidation reaction of an anode material and a reduction reaction of the cathode material. When lithium is heated to a level where lithium can undergo an explosive reaction using the low-temperature pyrolysis system, the binder, the electrolyte, and the separator contained in the waste lithium secondary battery are gasified into syngas by the explosive reaction of lithium and the resulting syngas is removed. The reduction reaction of the cathode material and the oxidation reaction of the anode material are promoted by the continuous explosive reaction of lithium and the stirring action of the spiral. As a result, the black powder and the current collector mixture are extracted. Therefore, it is possible to improve the recovery rate of valuable metals to more than 97%, thereby improving recycling efficiency.