Abstract: Rice starch-fatty acid complexes were prepared by compounding rice starch with different chain lengths of lauric acid (C12), myristic acid (C14), and palmitic acid (C16). By measuring the composite index, gelatinization properties, rheological properties, and in vitro digestion properties of the complex, the influence of fatty acid chain length on the properties of rice starch-fatty acid complex was explored. The results showed that compared with rice starch, the solubility, swelling, viscosity value, attenuation value, retrogradation value, viscoelasticity, and digestion properties of rice starch-fatty acid complex were all reduced. Fatty acids with different chain lengths had a significant impact on the properties of the complex (P<0.05), among which short chain fatty acids exhibited strong binding ability with rice starch. The composite index of the complex could reach 26.77%, and the fatty acid content in the complex was relatively low. As the length of fatty acid chains increased, the solubility, swelling, viscoelasticity, and resistant starch content of the complex decreased, while the viscosity value, attenuation value, and retrogradation value increased. When different long-chain fatty acids were combined with rice starch, the combination effect of short chain fatty acids was better. The research results can provide reference for the preparation of starch-fatty acid complexes with lower digestibility and anti digestible starch foods.