Mn-Co spinel catalysts with different Mn/Co molar ratios were prepared by coprecipitation method using Mn(NO?)?, Co(NO3)2?6H2O, KMnO4 and Na2CO3 as raw materials and characterized by XRD, BET, TEM, XPS, H2-TPR and O2-TPD. The catalytic oxidation of ethyl acetate by the catalysts was evaluated. The results showed that the change of Mn/Co molar ratio could change the active sites of spinel catalysts. When Mn/Co molar ratio was 1∶1, the prepared Mn1Co1Ox (2≤x≤3) had the most active sites and exhibited the best catalytic activity [Temperatures at 50% and 90% conversion of ethyl acetate (T50 and T90) were 151 ℃ and 164 ℃, respectively. And the activation energy (Ea) was 120.2 kJ/mol], which was directly related to the oxygen vacancy (OV) content, Mn4+ and Co2+ concentration on the surface of catalysts. The synergistic effects of OV and metal cation electron exchange (Co2++Mn4+?Mn3++Co3+) on the catalyst surface constructed "OV-Mn4+-O-Co2+" efficient active sites.