In this study， the effects of ultrasonic assisted acid extraction on extraction efficiency and physicochemical properties of acid-soluble collagen from sturgeon skin were studied. The results showed that the extraction rate of ultrasonic assisted acid-soluble collagen (UASC) (27.527% ± 0.65%) was significantly higher than that of conventional acid-soluble collagen (ASC) (7.330% ± 0.42%). SDS-PAGE and UV-vis analysis showed that both ASC and UASC were type I collagen. Fourier transform infrared spectroscopy (FTIR)， spectral fitting analysis of amide I band and X-ray diffraction analysis showed that ASC and UASC maintained relatively complete triple helix structure， and UASC had higher structural stability than ASC. The results of collagen viscosity and differential scanning calorimetry (DSC) indicated that the thermal stability of UASC was higher than that of ASC. Scanning electron microscope (SEM) analysis results showed that the microstructure of both ASC and UASC showed porous structure without significant structural differences. The results of this study indicated that ultrasonic-assisted acid extraction could effectively improve the extraction rate of collagen from sturgeon skin under certain conditions. The structure of sturgeon skin collagen was not damaged by ultrasound， but the structural stability and thermal stability of sturgeon skin collagen were improved. The research results provide important practical guidance for the application of ultrasonic-assisted extraction of collagen from sturgeon skin.