Abstract: The objective of this work was to investigate the refining technology and process conditions of active carbon decolorization of xylonic acid from insitu whole- cell catalysate of diluted sulfuric acid pre- hydrolyzed corn stover solution. Based on the single factor experiment,the orthogonal design was applied to select the optimal conditions for the decolorization of xylonic acid.The decolorization rate and the recovery rate of xylonic acid were used as indexes which were determined by UV- Vis spectrometer and high performance anion exchange chromatography,respectively. The experimental results showed that powdered activated carbon had selective adsorption function for all xylonic acid products from diluted sulfuric acid pre- hydrolyzed corn stover solution,the removal rate of pigment impurities was significantly higher than the adsorption rate of xylonic acid. C3 performed the best in the adsorption of coloring matters among the three kinds of activated carbon products.The amount of C3 was the most significant factor for decolorization,followed by time and temperature. The optimal conditions for decolorization as follow: the added quantity of activated carbon was 20%( w / w),the temperature was 60 ℃ and the time was 40 min.Under these conditions,the decolorization rate was 99.74% and the recovery rate was 90.05%. It indicated that it was a feasible,convenient and quick technology to decolor and refine of xylonic acid with powdered C3.