NOVELTY - A gas diffusion layer for fuel cell comprises a multi-hole parent metal (1) and a micro hole layer (2); where the micro hole layer is compounded on the surface of the multi-hole parent metal which is close to one side of the catalysis layer; the multi-hole parent metal (1) and the micro hole layer (2) are both prepared by hydrophobic processing; the fluorine polymers with hydrophobic function is included in the multi-hole parent metal (1) and the micro hole layer (2); and the fluorine polymer is only sintered by one time.    USE - The gas diffusion layer is useful for fuel cell (claimed).    ADVANTAGE - In the gas diffusion layer, the fluorine polymers of the multi-hole parent metal and the micro hole layers are all sintered at the same time and for once only; and the fluorine polymer aging caused by various sintering is avoided. Moreover, because the fluorine polymers of the multi-hole parent metal and the micro hole layers are all sintered primarily, the adhering capacity of both is enhanced.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is a preparation method of the gas diffusion layer for fuel cell comprising: (a) processing of the multi-hole parent metal: putting the multi-hole parent metal in the fluorine polymer latex with 5- 8% of concentration for 5-60 minutes, taking out the multi-hole parent metal for drying at room temperature or heating to dry the multi-hole parent metal at 40-200 degrees C; (b) carrying out preparation of the micro hole layer slurry: blending carbon soot, solvent with 80-140 degrees C of boiling point, and fluorine polymer latex with 5-80% of mass concentration, and uniformly scattering the solution; where the mass ratio of the carbon soot and the fluorine polymer is 1 0.01-1; (c) compounding micro hole layer and multi-hole parent metal: pasting, molding, rolling, spraying, printing or coating at 10-70 degrees C to compound the micro hole layer slurry obtained in (b) on the multi-hole parent metal which is pre-treated in (a); and (d) sintering the compound obtained in (c) at 210-400 degrees C for 5-120 minutes according to the difference of the fluorine polymer type, and taking out the compound to obtain the gas diffusion layer.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the gas diffusion layer for fuel cell.    Multi-hole parent metal (1)    Micro hole layer (2)