Abstract: To solve the problem of adverse influence on the environment exerted by the residue dye liquid from traditional dyeing of wool with acid mordant dyes by after-chroming,and to lessen the pressure of chromium-containing waste water treatment,the dyeing method was modified by adopting two-bath dyeing technique in which the initial dyeing liquid and mordant dyeing liquid could be used in the recycled way,thus saving dyestuff and reducing the drainage of chromium-containing waste water.The color shade,soaping fastness,and fastness to rubbing of the dyed samples by both traditional and new technique were tested and the results showed that the new technology can live up to the standard of the traditional dyeing and protect the environment as well.