Abstract: Acid-base composite membranes derived from sulfonated polybenzimidazole (S-PBI) and sulfonated poly(arylene ether sulfone) were prepared via solution blend process. Properties of the membranes were characterized in terms of swelling ratio in methanol aqueous solution，water uptake，methanol permeability coefficient and proton conductivity. Results indicated that the introduction of S-PBI reduced the methanol swelling and methanol permeability coefficient of the membranes. Although the proton conductivity decreased with the addition of S-PBI，the composite membrane showed a relatively high proton conductivity with certain S-PBI content at high temperature. Thus，the composite membranes could be used as proton exchange membranes for direct methanol fuel cell applications.