The most abundant source of renewable energy is lignocellulosic biomass on the planet.Every year worldwide production estimated lignocellulosic biomass to exceed 200 billion tons.Human being is trying hard to develop the bioethanol converted from lignocellulosic materials to replacement of petroleum-based automotive fuels.It can also provide numerous environmental and social benefits.However, the effective utilization of both glucose and xylose is the key point in the using of lignocellulosic biomass.Traditional yeast Saccharomyces cerevisiae can use glucose but the capable of utilize xylose lignocellulosic is limited.It will cause a great extent on the xylose substrate waste when producing bioethanol from lignocellulosic.At the same time the glucose repression effect exists in Saccharomyces cerevisiae.That is after the consumption of the glucose, Saccharomyces cerevisiae will use ethanol as a carbon source then acetic acid will be the final product, ethanol production will be reduced.In this study specific primers were designed.The xylA gene of the E.coli were cloned.About 300bp fragment of the two sides of Saccharomyces cerevisiae SC 18 strain SNF1 gene, xylA gene and loxp-kan-loxp gene were connected by fusion PCR method to obtain the full sequence of genes △SNF-xylA-kan.After subcloned to pMD18-T vector recombined transformation element p18-△SNF-xylA-kan were obtained.pl8-△SNF-xylA-kan was linearized and transformed to Saccharomyces cerevisiae SC18 strain.After selected by G418 resistance, the homologous recombination lines △SNF-xylA-kan successfully replaced SNF1 gene to the genome of Saccharomyces cerevisiae SC18 strain, after fermentation test the construct strains xylose metabolism capability has improved, and the glucose repression effect is suppressed.The capacity of xylose utilization increased by more than 40% compared with the original strain.Acetic acid production decrease 12.07% than the original strain.