Manganese oxide was obtained by selective chemical leaching of lithium ion out from the spent LiMn2O4 electrode materials and in-situ phase transformation.The prepared manganese oxide was characterized by X-ray power diffraction (XRD) and showed cubic λ-MnO2.The λ-MnO2 powder was found to be an effective catalyst for the synthesis of iso-amyl acetate from acetic acid and iso-amyl alcohol.The reaction results showed that when the leaching sulfuric acid concentration was 0.5 mol·L-1 and reaction time was 3 h,λ-MnO2 showed the best catalytic activity and excellent selectivity for esterification of iso-amyl acetate(yield 94.62%).