The present invention relates to a method for preparing starch syrup using a complex microbial fermented solution, and more specifically, to a method for preparing high quality and high functional starch syrup capable of obtaining an antioxidant effect. The method for preparing starch syrup using a complex microbial fermented solution according to one embodiment of the present invention includes a step of preparing a complex microbial fermented solution, a step of washing grains, a step of making hard-boiled rice, a step of fermenting in a fermentation for 6-9 hours, a stirring step, and a step of completing starch syrup by concentrating a fermented product.