Oleyl-branched oligosaccharide phosphate (OA-BOS-P) was prepared by phosphorylation through dry-heating branched oligosaccharide (BOS) from corn starch with metaphosphric acid, and then by oleylating the resulting branched oligosaccharide phosphate (BOS-P) through lipase-catalyzed solid phase synthesis. The multi-functionality of OA-BOS-P was evaluated in respect of its interfacial ability, Ca²⁺-binding ability, and ability to control the gelatinization and retrogradation behavior of potato starch. OA-BOS-P exhibited markedly lower surface tension and interfacial tension than either BOS-P or oleyl BOS (OA-BOS), and revealed Ca²⁺-binding ability similar to that of BOS-P. OA-BOS-P offered improved gelatinization behavior, as indicated by the elevated gelatinization temperature, reduced enthalpy, and reduced peak viscosity and breakdown, in comparison with those properties of other related samples. OA-BOS-P also inhibited retrogradation as indicated by the reduced setback viscosity, turbidity and development of an ordered structure depending on the level of addition, whereas BOS-P and OA-BOS elevated the turbidity, in spite of the reduced setback value and development of an ordered structure. OA-BOS-P could therefore be a useful multi-functional food material with interfacial, Ca²⁺-binding, and starchy food-controlling abilities.