The invention relates to a method for improving propionic acid yield by utilizing trehalose. The method comprises the steps of selecting an acid production propionibacterium original strain, determining a trehalose synthesis route of the acid production propionibacterium original strain, and building an acid production propionibacterium gene engineering original strain overexpressed by the trehalose synthesis route. According to the method provided by the invention, a biological conservation mechanism of the trehalose is utilized, so that the stability of a life process can be maintained, andthe self tolerance of the strain is improved; through overexpressing the trehalose synthesis route, the content of trehalose in cells is improved, the tolerance of the strain is improved, the pressureof a process for producing propionic acid through large-scale microbial fermentation is overcome, and the propionic acid yield is finally improved.