Denim washing is processed with different washing techniques such as stone washing, chemical washing, sand washing, and bio washing. Cellulase bio washing can meet environmental regulations that enhance and rectify problems associated with traditional decolorization techniques; however, stone washing needs to be added to the processing because it produces a low decolorization effect. There is also the problem of additional strength reduction. To prevent these problems, a new enzyme for bio washing is required. This study examines the optimum laccase treatment conditions on denim and evaluated the characteristics of laccase-treated denims to establish a database of eco-friendly new decolorization process on denim using a new laccase enzyme. The results show that the optimum conditions of laccase on denim are a pH of 4.0, $30^{circ}C$, 7% (o.w.f.), and 6 hours in 10 mM of buffer concentration. UV absorbance and HPLC identified isatin coexist with anthranilic acid in solution after laccase treatment on denim. Results of the surface color, the surface morphology and the tensile strength indicate that laccase treatment shows an excellent decolorization effect without fiber damage. The wet cleaning fastness and the perspiration fastness also improved.