The invention discloses a method for preparing sourdough steamed bread by using saccharomyces cerevisiae and lactobacillus sanfranciscensis, and the method comprises the following steps: (1) respectively taking and mixing the bacterial sludge of the saccharomyces cerevisiae and the bacterial sludge of the lactobacillus sanfranciscensis with flour and water uniformly, and obtaining the sourdough after fermentation; and (2) uniformly mixing the sourdough with flour and sodium bicarbonate, and after conducting dough kneading, cutting, rolling, molding and recovering, conducting steaming to obtain the sourdough steamed bread finished product. The method for preparing the sourdough steamed bread selects the predominant lactobacillus strain lactobacillus sanfranciscensis and the predominant saccharomycetes strain saccharomyces cerevisiae in the traditional sourdough, adopts a lactobacillus-yeast mixed fermentation mode, effectively improves the mouthfeel, flavor and texture of the steamed bread, overcomes the defect of insufficient flavor of the sold products fermented by single yeast on the existing market, simultaneously improves the nutrient value of the steamed bread and prolongs the preservation time of the steamed bread.