A method for producing a dyed or printed fiber product of a brilliant color, which comprises dyeing or printing a fiber material with a blue reactive dye composition comprising a phthalocyanine dye represented by a free acid of the following formula (I), ##STR23## wherein CuPc is a copper phthalocyanine nucleus, W is a C.sub.2 -C.sub.4 alkylene group or a 1,3- or 1,4-phenylene group having one or two sulfo groups, R.sub.1 and R.sub.2 are independently a hydrogen atom or a lower alkyl group, l is a number of 1 to 3, m is a number of 0 to 2, and n is a number of 1 to 3, provided that the total number of l, m and n is 4 or less, and a phthalocyanine dye represented by a free acid of the following formula (II), ##STR24## wherein CuPc, l, m and n are as defined above, Y.sub.1 and Y.sub.2 are independently a hydrogen atom or a methyl, methoxy or sulfo group, R.sub.3 is a hydrogen atom or a lower alkyl group, and Q is --SO.sub.2 CH.dbd.CH.sub.2 or --SO.sub.2 CH.sub.2 CH.sub.2 Z in which Z is a splittable group by the action of an alkali, the mixing weight ratio of the dyes (I) to (II) in terms of a copper content being from 80 through 20 to from 20 through 80, optionally together with the other color dye(s).