The invention provides a yellow reactive dye composition and dyeing application and method thereof on fibers. The composition comprises one or more dye compounds shown in the general formula (I) and one or more dye compounds shown in the general formula (II), wherein the dye compounds are mixed in a certain proportion. Fastnesses, especially light fastness and wet treatment fastness, of the reactive dye composition are excellent, and the dye composition can be widely used in coloring of cellulose fibers, polyamide fibers, protein fibers, blended textiles and the like. The dye composition has an unexpected coloring effect during union dyeing of kam cotton blended textiles by means of the one-bath and one-step method. Please see the formulas in the description.