Abstract: A composition of a water-repellent agent has a solvent and a solute. The solvent is water. The solute is dissolved in water and has isocyanate-acryl, non-ionic fluoro-acryl, 4,4-dipheylmethane diisocyanate, zinc acetate and polyethylene wax. Isocyanate-acryl has a concentration in a range of 10˜40 gram in per liter of the water-repellent agent (i.e. 10˜40%). Non-ionic fluoroacryl has a concentration in a range of 80˜150% t. 4,4-dipheylmethane diisocyanate has a concentration in a range of 5˜12%. Zinc acetate has a concentration in a range of 1˜20%. Polyethylene wax emulsion has a concentration in a range of 1˜40%. Therefore, a fabric treated with the present invention has good waterproof ability, widely enhanced color fastness in light and improved tear-resistance strength at the same time.