The paper deals with the effect of the dyeing rate and the fixation rate because of the alterable pH value in the dyeing of wool with reactive dyes of wool.In the initial stage,the pH value of dye bath containing(NH 4) 2SO 4 equates about seven,so uniform dyeing can be achieved.With the temperature rising,(NH 4) 2SO 4 decomposes into volatile NH 3 and H 2SO 4.That the pH value is gradually declining results in the covalent bonding between the fiber and the dye and getting high dyeing rate and fixat...