Glycerol monostearate (GMS) was reported to reduce starch digestibility. Thus, this study aimed to investigated whether GMS could modulate the starch digestibility of diacylglycerol (DAG) mooncakes. Increasing concentrations of GMS were incorporated into the mooncake dough and their impact on the formation of starch-lipid complexes was examined. At 1.2% GMS content, the resistant starch content was 30.52%. Complex index analysis indicated that the increase in resistant starch content was mainly attributed to the formation of complexes between GMS and amylose. X-ray diffraction patterns showed that GMS addition increased the relative crystallinity from 6.50% to 23.96%. Differential scanning calorimetry analysis also demonstrated that GMS addition resulted in a significant increase in enthalpy change, from 188.0 to 328.3 J•g-1. Fourier-transform infrared spectroscopy further revealed that GMS enhanced the short-range ordered structure of DAG mooncake dough. Therefore, incorporating an appropriate amount of GMS (1.2%) into DAG mooncakes can substantially decrease their starch digestibility, providing theoretical basis for the development of functional foods.