A large amount of dye wastewater poses a threat to environmental safety. Disperse blue, an anthraquinone dye that is widely used in textile dyes, is difficult to degrade in wastewater. In this work, one fungus was screened according to the decolorization rate of disperse blue. The fungus was identified and named Aspergillus XJ-2 on the basis of its morphological characteristics and 18s rDNA. Response surface method was used to optimize culture conditions for A. XJ-2. The optimum values of obtained responses were as follows: temperature, 35 °C; pH, 5.2; carbon-to-nitrogen ratio, 30:5.5; and rotation ratio, 175 r·min-1. Under optimized conditions, the decolorization rate of A. XJ-2 was up to 94.8% in 48 h.