Abstract: The effects of fatty acid unsaturation on the thermal properties,microstructure,particle distribution and Zeta potential of high amylose corn starch-fatty acid complexes were investigated. The results showed that the stability decreased when complexes achieved with high amylose corn starch and fatty acid, the thermal stability of starch-fatty acid complexes decreased with the increase of fatty acid unsaturation. The V-type crystal structure of high amylose corn starch-fatty acid complexes was formed and the crystallinity decreased with the increasing of unsaturation. There were two forms of high amylose corn starch-fatty acid complexes,which were convex spherulites on the surface of particles and layered or flocculent structure embedded on the surface of the particles,and the existence of the latter decreased with the increase of the number of double bonds in the fatty acids. The particle size of starch became smaller and the stability of dispersion increased compared with control starch. In conclusion,there was significant influence of fatty acid unsaturation on the structure and thermal properties of high amylose corn starch-fatty acid complexes.