Abstract: In order to improve the smoothness of slendrized wool fibres to the extent of approaching the cashmere fiber , the alkaline protease (Savinase) was used in the treatment of slenderized wool top to remove the raised part of scales generated from wool slendering. The amount of protease used and the treating time were varied in the process. Based on the observation of wool morphology and the testing of the weight loss, frictional coefficient and the tensile properties, the feasibility of removing the raised scales with protease was verified. The results showed that the best effect is obtained with 1.6%(o.w.f) protease when treating for 40 min.