A membrane electrode assembly for fuel cell, a method for preparing the same and a fuel cell comprising the same

Provided are a membrane electrode assembly which is improved in durability, is reduced in the diffusion velocity of methanol at an anode catalyst layer and is enhanced in the supply of air and the discharge of water at a cathode, its preparation method, and a fuel cell containing the membrane electrode assembly. The membrane electrode assembly comprises an anode(10) which comprises an anode substrate(12), an anode diffusion layer(14) and an anode catalyst layer(16) having pores; a cathode(20) which comprises a cathode substrate(22), a cathode diffusion layer(24) and a cathode catalyst layer(26) having pores; and an electrolyte membrane(50) which is located between the cathode and the anode, wherein the anode diffusion layer is hydrophilic, the cathode diffusion layer is hydrophobic, and the average diameter of the pores of the anode catalyst layer is smaller than that of the cathode catalyst layer. Preferably the anode diffusion layer contains 5-20 wt% of polytetrafluoroethylene; and the cathode diffusion layer contains 20-50 wt% of polytetrafluoroethylene.