The invention discloses an all-component harmless recycling method of waste lithium ion battery. the method comprises the following steps: pre-sintering the waste lithium ion battery in a resistance furnace, mechanically crushing the pre-sintered waste lithium ion battery, and sorting to obtain positive pole plates and negative pole plates; performing wet stripping on the positive and negative pole plates to achieve an aim of efficiently separating positive active materials and the carbon powder from the aluminum and copper foil, wherein the recycling rate of the lithium-nickel-cobalt-manganese in the separated positive active material is greater than 99%, and the content of each of the aluminum and copper in the positive active material is less than 0.05%. The method disclosed by the invention is simple and easy to realize, two-stage harmless absorption treatment is performed on the electrolyte and organic substance which are hard to recycle in the pre-sintering process, and the problem that the electrolyte volatilizes to pollute the environment in the crushing process of the waste lithium ion battery is solved. The positive active material in the waste lithium ion battery is effectively and thoroughly separated from the aluminum foil by using the wet stripping, and valuable metals in the positive active material containing the nickel, the cobalt, the manganese and the lithiumare efficiently recycled through a wet recycling procedure. The method disclosed by the invention is short in process flow, low in production cost, environment-friendly, and easy in industrialization