Abstract: This study investigated the effects of three distinct pre-extraction treatments—acid, enzymatic and ultrasonic—combined with hot-water extraction on the yield, structural features, physicochemical properties, rheological behaviour, gel strength and functional performance of gelatin derived from dehaired sheep skins, with the aim of identifying an optimal processing strategy. Ultrasonic pretreatment produced the highest extraction yield (65.13%), significantly exceeding that of acid (42.31%) and enzymatic treatments (36.62%) (P<0.05). In contrast, acid pretreatment yielded the highest purity (92.4%), followed by the ultrasonic method (90%). Structural analyses revealed that gelatin from the ultrasonic group retained the most intact collagen architecture: SDS–PAGE showed well-defined α-chains, FTIR spectra indicated greater hydrogen-bond preservation, and circular dichroism analysis revealed an α-helix content of 37.5%, markedly higher than those of the acid (5.3%) and enzymatic (10.6%) groups (P<0.05).In terms of rheological and gel-forming properties, the ultrasonic group displayed superior melting temperature (39~42.7 ℃), dynamic viscosity, a higher proportion of high-molecular-weight fractions (≥10 kDa, 75.68%) and greater gel strength (273.7 g). Its functional attributes—including emulsifying activity (12.46 m²/g), emulsion stability (842.13 min), foaming capacity (140.65%) and foam stability (20.94%)—were also significantly enhanced relative to the other treatments (P<0.05). Amino-acid profiles did not differ significantly among treatments (P>0.05), with glycine and proline remaining predominant. Collectively, these findings demonstrate that ultrasonic pretreatment simultaneously improves extraction efficiency, preserves molecular integrity and markedly enhances both gelation and interfacial properties, establishing it as a preferred strategy for producing high-quality sheep-skin gelatin and supporting its broader application in the food industry.