In order to fully reveal the heat-response mechenism of yeast,the content of trehalose in heat-resistant yeast Saccharomyces cerevisiae under heat stress was determined,and the expression of the genes involved in the trehalose metabolism was analyzed via the real-time quantitative polymerase chain reaction.The results show that,under the heat stress at 42℃,the content of intracellular trehalose significantly is up to 0.20g per gram of dry cell after 240min,which is about 4 times that without heat stress,and that,with the further prolonging of stress time,the content of intracullar trehalose decreases.The change of expression of the genes involved in the trehalose metabolism shows high consistency with that of the content of intracullular trehalose,which means that trehalose plays an important role in the adaptive process of yeast to a high temperature.