NOVELTY - A gas diffusion layer of fuel cell comprises pre-processed layer and gas diffusion sub-layer sequentially provided on porous substrate.    USE - Gas diffusion layer for galvanic pile and electrode used for membrane electrode assembly of fuel cell (all claimed).    ADVANTAGE - The gas diffusion layer provides membrane electrode with improved mass transfer property and heat transfer property.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) manufacture of gas diffusion layer, which involves forming pre-processing layer by coating porous substrate using mixed solution formed by mixing low-molecular-weight alcohol with conductive carbon material and binder, and cooling to 3-10 degrees C for 20-60 minutes;    (2) electrode, which comprises catalyst layer provided on gas diffusion layer;    (3) membrane electrode assembly comprising proton exchange membrane, catalyst layers at the two sides of the proton exchange membrane and the gas diffusion layers with different sizes, positioned at the two sides of the catalyst layers wherein the two ends of the gas diffusion layer are provided with polyester pieces, be stuck and fixed between the gas diffusion layer and the proton exchange membrane by the macromolecule glue; and    (4) manufacture of membrane electrode assembly, which involves cutting off the gas diffusion layer into two sheets in different sizes, placing the sheets at the two sides of the proton exchange membrane coated with the catalyst layer, placing the polyester pieces at the two ends of the gas diffusion layer, binding the polyester pieces between proton exchange membrane and gas diffusion layer using macromolecule glue and thermally pressing, or coating the catalyst layer on the gas diffusion layer so as to form the electrode, cutting the electrode into two sheets with different sizes, placing the two sheets at the two sides of the proton exchange membrane, placing the polyester pieces at the two ends of the electrode, binding the polyester pieces between proton exchange membrane and electrode using macromolecule glue and thermally pressing.