Abstract: To investigate the effects of modification methods on the structure and functions of hulless barley starch, black hulless barley starch was treated with electron beam irradiation, dry heat treatment, pulsed magnetic field, and octenyl succinic anhydride (OSA) grafting. The structure, solubility, thermodynamic properties and in vitro digestive properties of the samples before and after treatment were analyzed. The results showed that compared with the untreated group, all four modification methods reduced the amylose content, among which electron beam irradiation exhibited the most significant effect with a reduction rate of 19.63%. Dry heat treatment led to a remarkable increase in starch particle size, while the other treatments had relatively minor effects. After modification with different methods, the surface roughness of starch granules increased with the appearance of breakages or pores, the ordered structure of starch decreased and the crystallinity declined, with electron beam irradiation and dry heat treatment exerting more pronounced effects. The gelatinization onset temperature (To), peak temperature (Tp), conclusion temperature (Tc) and enthalpy change (ΔH) of the four modified starches all decreased significantly (P<0.05), indicating a reduction in the thermal stability of starch. Modification could enhance the solubility, swelling power and paste transparency of starch, among which the electron beam irradiation group had the highest solubility and paste transparency, reaching 3.89% and 15.09%, respectively. In vitro digestion analysis revealed that the content of rapidly digestible starch (RDS) increased after different modification treatments, whereas the contents of resistant starch (RS) and slowly digestible starch (SDS) decreased, with dry heat treatment and OSA grafting showing more significant effects. Overall, all the tested modification methods caused certain damage to the structure of hulless barley starch, but improved its solubility and swelling properties. This study can provide a theoretical basis for the modification of hulless barley starch and its high-value application in the food industry.