The invention discloses a method for recovering positive electrode materials of waste lithium ion batteries based on a mechanochemical method, belonging to the field of recycling waste lithium ion batteries. Grinding the positive electrode material of the waste lithium ion battery into powder, and fully mixing with an activator and an organic reducing agent, the activator can generate active free radicals to obtain a mixture, and the mixture is ball milled to make the positive electrode of the waste lithium ion battery The material undergoes plastic deformation, and lattice defects are generated in the crystal particles, so that the crystal particles undergo crystal transformation or amorphization; the ball-milled product is added to deionized water to leach valuable metal ions. The method in the present invention does not rely on high-concentration strong acid, strong alkali, strong redox reagent or expensive organic acid, etc., and takes the mechanochemical reaction in the solid phase as the main body of the reaction to realize the waste lithium ion extraction in a mild leaching environment. Efficient leaching of valuable metals such as lithium, cobalt, nickel, manganese and other valuable metals in battery cathode materials.