Abstract: In this paper,Curvularia lunata strains were mutagenized by UV-⁶⁰Co-γ,microwave and diethyl sulfate. By means of the mutation treatment, the laccase ability of C. lunata substantially increased from 0.55 μmol/(min·mL)to 1.949 μmol/(min·mL). In order to increase the laccase ability further, the single factor experiment and orthogonal design experiment were carried out, the result indicated that the optimal conditions were as follows: fermentation temperature 30 ℃, fermentation time 72 h, culture medium pH 6, liquid volume 120 mL, rotation rate 160 r/min, potato 200 g/L, sucrose 30 g/L, soy peptone 5 g/L, KH₂PO₄ 5 g/L, guaiacol 0.2 mmol/L, Tween 80 0.1 mL/L, Mg²⁺ 0.5 mmol/L, Cu²⁺ 1 mmol/L, Ca²⁺ 1 mmol/L, Mn²⁺ 0.25 mmol/L. Ultimate laccase activity 2.306 μmol/(min·mL).