Abstract: The xylan was hydrolysed with low concentration trifluoroacetic acid (TFA ) in dissolving pulp,then the optimum conditions were obtained by orthogonal test and response optimization.The results showed that at the conditions of TFA concentration 0.15%, temperature 116.3 ℃,and reaction time 9 h, all xylose can be removed with only 3.2% glucose losses. The study provides a new method to remove residual hemicellulose in dissolving pulp.