Starch is a readily available and abundant source of biological raw materials and is widely used in the food, medical, and textile industries. However, native starch with insufficient functionality limits its utilization in the above applications; therefore, it is modified through various physical, chemical, enzymatic, genetic and multiple modifications. This review summarized the relationship between structural changes and functional properties of starch subjected to different modified methods, including hydrothermal treatment, microwave, pre-gelatinization, ball milling, ultrasonication, radiation, high hydrostatic pressure, supercritical CO₂, oxidation, etherification, esterification, acid hydrolysis, enzymatic modification, genetic modification, and their combined modifications. A better understanding of these features has the potential to lead to starch-based products with targeted structures and optimized properties for specific applications.