The invention discloses a preparation method of a low-cost milk-aroma base material with a toffee flavor. The preparation method comprises the steps as follows: (1) a substrate is weighed, water, an auxiliary substrate and ethyl maltol are added, and the mixture is sterilized and cooled to 35-45 DEG C; (2) lipase A12 is added, enzymolysis is conducted at 35-55 DEG C for 3-24 h, and enzyme deactivation treatment is conducted, so that an enzymatic hydrolysate A is obtained; (3) protease MSD is added to the enzymatic hydrolysate A, enzymolysis is conducted at 35-55 DEG C for 3-24 h, and enzyme deactivation treatment is conducted, so that an enzymatic hydrolysate B is obtained; and (4) the enzymatic hydrolysate B is subjected to centrifugation treatment, and an upper oil phase is taken, so that the milk-aroma base material with the toffee flavor is obtained, wherein the substrate is a mixture of cream and palm oil. The milk-aroma base material with the toffee flavor is prepared with the cream and the palm oil used as the substrate, the obtained milk-aroma base material has strong and true aroma, long aroma retention time and remarkable toffee flavor and sweet aroma and has higher yield and lower cost as compared with base materials with pure cream used as the substrate.