Abstract: Objective:To establish a method of trehalose extraction from yeast,and compare trehalose content from beer yeast(Saccharomyces cerevisiae),Saccharomyces ellipsoideus,high-activity dry yeast(Saccharomyces cerevisiae),high-activity Saccharomyces cerevisiae. Methods:Yeast was grinded firstly in liquid nitrogen,and then of extracted trehalose with ethanol-water solution by ultrasonic assisted,trehalose content was analysed by high performance liquid chromatography(HPLC-RI). Saccharomyces cerevisiae as a material,extraction conditions of trehalose was optimized by orthogonal experiment based on single factor experiment. The content of trehalose from four edible yeast strains was compared.Results:The results showed that the optimal method for extraction of trehalose were as follows :extraction temperature 80℃,ethanol concentration 50%,ratio of material to water 1∶15(g∶m L),extraction time 70 min,then the yield of trehalose was(68.10±0.7)mg/g. The order of trehalose content of four edible strains was Saccharomyces cerevisiae>high-activity dry yeast(Saccharomyces cerevisiae)>Saccharomyces ellipsoideus>beer yeast(Saccharomyces cerevisiae). Conclusion:Optimization of yeast trehalose extraction process was simple,high extraction efficiency. Methodology investigation results showed that analysis the content of trehalose by HPLC-RI was accurate,repeatability,convenient and quick.The content of trehalose from the yeast strains different production uses was different.