Membrane Electrode Assembly (MEA) is a key component of direct methanol fuel cell. In order to improve the power generation performance of the MEA, it is necessary to reduce polarization losses. The cathode and anode activation polarization, proton exchange membrane ohmic polarization and gas diffusion layer mass transfer polarization were studied under different methanol concentration and operation temperature conditions respectively. A theoretical study of the various polarization fitting and distribution losses was conducted. The polarization distribution results indicated that the activation polarization of cathode and anode are the main over potential contribution and accounted for more than 80%. The ohmic resistance accounted for approximately 10%. By studying the distribution of polarization loss, we got a variety of distribution of polarization losses under different operating conditions, these results provide a theoretical basis for efficient ways to optimize the MEA. (C) 2016 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.