Abstract: In order to modify the wool with biological method, this paper investigated the activity and the best catalyzed oxidation conditions for preparation of Tyrosinase from potatoes using a simple and easy method with catechol (catecha phenol) as substrate. And the potato tyrosinase was used to treat the wool fabric. FTIR-ATR spectroscopy and the mimic complexes with－NH2 were used to examine whether the wool had occurrd oxidation reaction after enzymatic treatment. The results indicated that maximum absorbance wavelength of the self-made potato tyrosinase enzyme-induced reaction product is 410 nm with catechol as substrate, the best reaction condition is at 30 ℃ and pH 6.8. This research proved that tyrosine residue in wool was oxidized to dopa-quinone.