Abstract: According to recovery efficiency of oat protein, clearance efficiency of total sugar, degree of membrane fouling, concentration efficiency and recovery efficiency of flux of the factors, the optimum conditions for separating oat protein with hollow fiber ultrafiltration membrane and cleaning method were determined. The best operating conditions of the MOF503 were as follows: temperature 35℃, pressure 0.02 MPa, pH 8 and flow rate 25 L/h. Under these conditions, the results of recovery efficiency of oat protein, clearance efficiency of total sugar, degree of membrane fouling, concentration efficiency were 80.3%, 79.5%, 41%, 43.5 L/(m2·h), respectively. And the batch ultrafiltration method supplementing with backpressure-flushing was better than other methods to separate oat protein. Through the experiments of physical and chemical cleaning with MOF503, the optimum conditions of cleaning with isotonic and backpressure-flushing water were determined, and the cleaning effect of backpressure-flushing water was the best, and the optium chemical cleaning agent was HCl (pH 2) and NaOH+H2O2+HCl. If the physical and chemical cleaning were used alternately, recovery efficiency of flux can be up to more than 94.74%. The work indicat that separating oat protein with hollow fiber ultrafiltration membrane is feasible, and it will be a base for researching into separating protein with membrane.