In this paper, the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO2 material. The ammonia reduction leaching mechanism of LiCoO2 material in the ammonia-sodium sulfite-ammonium chloride system was elucidated. Compared with untreated LiCoO2 material, the leaching equilibrium time of LiCoO2 after ball-milled for 5 h was reduced from 48 h to 4 h, and the leaching efficiency of lithium and cobalt was improved from 69.86% and 70.80% to 89.86% and 98.22%, respectively. Importantly, the apparent activation energy and leaching kinetic equation of the reaction was calculated by the shrinking core reaction model, indicating that the reaction was controlled by the chemical reaction.