To investigate the effects of different processing methods on the structure and physicochemical properties of highland barley starch, this study used highland barley as the raw material to analyze the effects of four processing methods, namely, stir-frying (at 260 ℃ for 15 s), steaming (steaming in boiling water for 65 min), normal-pressure boiling (boiling in boiling water for 55 min), and high-pressure boiling (boiling in boiling water for 38 min), on the structure, physicochemical properties, and in vitro digestibility of highland barley starch. The results suggested that the raw starch particles were smooth and plump; The stir-fried starch was severely shrunk and aggregated; The steamed starch slightly expanded and wrinkled; The atmospheric boiled starch expanded, ruptured, and adhered together; The pressure boiled starch completely disintegrated. The boiling process severely damaged the structure and crystal structure of highland barley starch particles, with the relative crystallinity of the boiled starch being 5.61% (atmospheric boiling) and 4.77% (pressure boiling). Moreover, different processing methods led to changes in the gelatinization and thermal properties of highland barley flour. Typically, the gelatinization viscosity of highland barley starch under atmospheric boiling was only 26.67 cP, while that of stir-fried starch changed slightly, being 343 cP. Additionally, all the processing methods inhibited the retrogradation of starch, and the strongest anti-aging effect was achieved under atmospheric boiling, with a retrogradation value of 17 cP. As revealed by the analysis of sedimentation characteristics, the aging degree followed the tendency of atmospheric boiled starch>stir-fried starch>normal-pressure steamed starch>pressure boiled starch>raw starch. According to thermal property analysis results, the enthalpy value of pressure boiled starch exhibited the greatest change from 993.63 J/g (raw starch) to 759.89 J/g (pressure boiled starch), further confirming that pressure boiling had the most significant damage to the starch structure. In terms of rheological properties, all the starch pastes showed a shear-thinning fluid dominated by elasticity (G'>G'', tanδ<1). The values of G' and G'' increased with the increase in angular frequency, and the G' value of stir-fried starch demonstrated the most obvious increase. The tanδ value of pressure boiled starch showed irregular fluctuations, indicating the most thorough structural damage. By contrast, the tanδ values of starch under other processing methods fluctuated more gently, almost consistent with the raw starch state, suggesting the insignificant damage to their crystal structures. All treatments significantly increased the content of resistant starch (RS) (P<0.05), while atmospheric boiling and pressure boiling had the best enhancement effects, increasing from 63.55% to 69.10% (atmospheric pressure boiled starch) and 68.35% (pressure boiled starch), respectively. Therefore, they may be the processing methods for developing highland barley as a staple food. Stir-frying increased the RS content, but caused the soaring of the rapidly digestible starch (RDS) content to 31.79% and the slowly digestible starch (SDS) content of only 0.72%, which may cause a sudden increase in blood sugar. Boiling could reduce the RDS content and retain a part of SDS, helping to maintain the relatively stable blood sugar level. This study provides a solid theoretical basis and scientific guidance for the development and utilization of hulless barley resources. It holds positive significance in enriching the processing methods of hulless barley and is expected to promote its broader application in the food industry.