The invention relates to a reactive golden yellow dye and a composite reactive brown dye. The reactive golden yellow dye is shown in a formula (I), while the composite reactive brown dye is prepared be compounding the reactive golden yellow dye shown in formula (I), C.I reactive orange 107, reactive dark blue M-R, C.I reactive blue 203, reactive dark red and reactive red SHE according to the mass ratio of (30-55): (5-12): (5-15): (5-15): (5-15): (5-15). The dyes can be used for dip dyeing, continuous pad dyeing, cold batching and shortened wet steaming processes, are low in directness, moderate in reactivity and high in product solubility, and have 1/1 dyeing depth, grade 5 of fastness to light, grade 4-5 of fastness to soaping, grade 4-5 of fastness to perspiration, grade 4 of fastness to chlorine water, grade 4-5 of fastness to dry rubbing, grade 4 of fastness to wet rubbing and grade 4 of fastness to ironing, and particularly, the phenomena of metamerism of redness and thermosensitive discoloration of a lamp A are improved obviously.