To provide a new dyeing system for a nylon pile fabric having at least one cobalt-containing metal dye and at least one unleveling acid dye without using a chromium-containing metal dye.

This dyeing system favorably and effectively colors a pile fabric and dramatically improves durability to bleaching agent. The colored pile fabric is used as a constituent material of a floor mat article requiring a periodic cleaning by a prepared substance generally containing a bleaching agent. The colored fabric hardly shows fading even after continuous and periodic severe cleanings. A floor mat containing the colored pile fabric and a dye composition itself are also provided. A method for coloring a pile fabric using the dyes, includes a heated surface overspread treatment so as to improve resistance to color fading by light and resistance to color fading by cleaning.