Abstract:The ultrasonic assisted freeze-thaw extraction method of β-glucan from oat bran was explored.The ultrasonic extraction，evaporation concentration and freeze-thaw repeatedly was used.The yield，purity，water holding capacity and viscosity of oat bran β -glucan were studied.The structure of oat bran β -glucan was characterized by Ultraviolet and infrared spectra.The results showed that the optimal ultrasonic assisted extraction：the solid-liquid ratio was 1 ∶20（g/mL），the ultrasonic power was 500 W，the extraction temperature was 55℃，the extraction time was 50 min，and the extraction liquid were evaporated and concentrated to 4.0 % of the volume.The yield of oat bran β-glucan was 6.0 %，the purity was 82.3 %，and the water holding capacity was 307.6 %.The UV and IR spectra of β-glucan extracted from oat bran were consistent with those of standard β-glucan.The method of ultrasonic assisted freeze-thaw was reasonable，and oat bran β -glucan with high purity，water holding capacity and viscosity could be obtained.