Abstract: The use of biomass hydrolysate,pentose,has always been a difficult problem. Increasing the utilization of pentose can reduce the waste of lignocellulose and increase ethanol production. In this paper,a mutant strain of Candida tropicalis bred by UV mutagenesis capable of utilizing xylose was obtained by Dux tube method and TTC chromogenic method,and fermentation experiments were carried out to determine the fermentation and the efficiency of co-fermentation of hexose and pentose. Then,the fermentation mechanism was discussed through metabolic network and metabolic equations and mathematical matrix.The results showed that,the utilization of glucose by the original and mutant strains was good,and the utilization rates were close to 95% and 96%,respectively. However,the utilization rate of the original strain xylose was low,and the ethanol yield was only 17.58 g/L. The ethanol yield of the mutant strain T70-2 was 22.85 g/L,and the utilization rate of xylose was 92.2%. Therefore,the mutant strain obtained in this study was capable of achieving co-fermentation of pentose and xylose.