Abstract: This work mainly explores the influence of the interface composition of lipid droplets on the digestive properties, and provides a theoretical basis for the development of lipid droplets with polar lipid interfaces. In this work, total lipids were extracted from buttermilk powder, and then milk polar lipid concentrate (MPL) was extracted by acetone concentration, The content of polar lipids in the concentrate was 30.5% measured by ³¹P-NMR. MPL and sodium caseinate (CN) were uniformly dispersed in phosphate buffer (water phase), respectively. Then, the oil phase was mixed with the water phase at a ratio of 8% (m/m), and after shearing, lipid droplets with the same particle size but different interface compositions were obtained. Based on an infant in vitro gastrointestinal digestion model, the mean particle size, Zeta-potential, free fatty acid release, glyceride composition and fatty acid composition at the end of digestion of lipid droplets during digestion were analyzed. In this way, the effect of different interfaces of lipid droplets on digestive properties was explored. The results showed that compared with lipid droplets with CN as interface, lipid droplets with MPL as interface had a higher release of fatty acids during digestion. The TAG content of lipid droplets with CN as interface was 11.22% at the end of digestion, while the TAG content of lipid droplets with MPL as interface was 8.15%, indicating that lipid droplets with MPL as interface had a higher lipolysis rate. From the change of particle size during the digestion process, the lipid droplets in the MPL group produced more small lipid droplets during the digestion process, indicating that more large lipid droplets were hydrolyzed. Zeta-potential results showed that the potential values of lipid droplets with MPL as interface during digestion were lower than those with CN as interface, indicating that lipid droplets in the MPL group had a strong electrostatic repulsion and good stability during digestion, which is conducive to the digestion reaction. At the end of digestion, the lipid droplet with MPL released more free palmitic acids, monoolein and monolinolein than that with CN.