Aqueous polyurethane making method used for superfine fiber synthetic leather production

The invention relates to an aqueous polyurethane making method used for superfine fiber synthetic leather production. The method using a superfine fiber synthetic leather base cloth as a substrate comprises the following steps: knifing release paper with a surface layer slurry containing an aqueous polyurethane finishing agent, an aqueous color paste, nanometer silica, a wetting agent, a coupling agent and a cross-linking agent to form a surface layer, and drying; knifing the surface layer with a bonding slurry containing an aqueous polyurethane adhesive and the cross-linking agent, and applying to the superfine fiber synthetic leather base cloth; and drying, cooling, and peeling to obtain he superfine fiber synthetic leather with an aqueous polyurethane coating. The method solves the solvent pollution problem of superfine fiber synthetic leather production, and the peel strength, the surface color dry web fastness, the surface color wet rub fastness and the water permeability of the superfine fiber synthetic leather obtained in the invention are greater than 20(N/20mm), greater than 4 grade, greater than 3.5 grade, and greater than 1.1(mg/cm .h).