Abstract: Light-weight coating fibers were treated by cellulase systems of different F/C value(ratios of filter paper activity to carboxymethyl cellulose activity) respectively.The distribution frequency of fiber lengths(<0.2 mm) decreased from 23.55% to 17.50%,average length of fiber increased from 1.067 mm to 1.168 mm,curl coefficient descended from 0.103 to 0.087 and kink coefficient increased from 0.78 entries/mm to 0.84 entries/mm with F/C value increasing from 0 to 2.5.When F/C value increases,the effect of outer-cut enzyme strengthens,average lengths of secondary fibers increase,fines and the curl degree decreases.Drainage properties of secondary fibers are improved.Kink degree of fibers rises and strengths of single fiber and paper decrease.