Abstract. Wastewater discharged from printing and dyeing plants on both sides of the Yangtze River seriously threatens the ecological and water security. Direct Blue 6 is a synthetic chemical dye and widely used in textile and dyeing industry. In this study, Pseudomonas aeruginosa HS-DY012 was used as a original strain in the decoloraziation of Direct Blue 6. Results indicated that HS-DY012 strain could completely decolorize and degrade 30 mg/L Direct Blue 6 dye in MSM medium within 18h culturing at 35 ℃ on a shaker at 120 rpm. The optimum condition of decolorization and degradation were determined, i.e. temperature at 35℃ and pH7.0, and the optimum concentration was 30 mg/L. HS-DY012 strain could effectually decolor seleted two type dyes both Reactive Black 5 and Congo red with a high degradation rate, as well as Acid scarled GR and Vat Yellow 2 could be decolored partially.These results indicated that HS-DY012 strain was a great degrader with a broad-spectrum dye decolorization character and it has a potential application.