The invention discloses a synchronous culture method for improving yeast biomass and intracellular trehalose content, belonging to the field of microbial fermentation. Through a synchronous culture mode of simultaneously carrying out fed-batch culture and temperature-changing culture, the method improves the yeast cell biomass as well as greatly improves the accumulation content of intracellular trehalose of yeast cells, thus remarkably improving the yield of yeast trehalose. In the method, fed-batch culture and temperature-changing culture are completed in one step, so the method has the advantages of simple process, convenient operation, short production cycle and low production cost.