A wild Ganoderma strain was isolated from Furongzhang in Huadu,Guangzhou. It was identified as Ganoderma weberianum by its morphological and molecular characteristics. The culture conditions for laccase production by Ganoderma weberianum was optimized in liquid fermentation and the discoloration ability of crude laccase for indigo dye was investigated. The results showed that wheat bran and glucose were the best carbon source for laccase production by Ganoderma weberianum and their optimal concentration were 35 g/L and 10 g/L,respectively. Yeast extract was the best nitrogen source for laccase production and its optimal concentration was 2.5 g/L. Cu2+ could enhance laccase production. Laccase activity in the ferment medium under the optimal culture conditions was 10 943.8 U/L after 6-day incubation,which was 68.3 fold of that of the original medium. Under the condition of pH3.0 and 50 ℃,indigo dye could be decolorized effectively by crude laccase,the decolorization rate reached 92.6% after 120-min reaction.