The invention discloses a composite proton exchange membrane. The composite proton exchange membrane is formed by a sulfonated polyvinyl alcohol solution with sulfonation degree of 10%-25% and a mixedsolution of the polyamide acid through casting membrane-forming, and is a composite membrane prepared by taking the polyimide as the matrix and taking the sulfonated polyvinyl alcohol as the dopant.The preparation material is extensive in source, simple in preparation process, simple in instrument preparation, and reduces the membrane-making cost. The sulfonated polyvinyl alcohol and the polyimide are compounded so as to weaken the conductivity drop of the proton, effectively reduce the methanol permeability of the composite proton exchange membrane and improving the comprehensive performance of the proton exchange membrane. A problem that the high methanol permeability is existent since the Nafion membrane produced by the Dupont company is used for a direct methanol fuel battery is solved, and the proton conductivity can satisfy the requirement on the proton exchange membrane by the direct methanol fuel battery; the exchange membrane can be used for the direct methanol fuel battery,and can be used for the direct ethanol fuel battery and like alcohol fuel batteries.