Abstract: The secondary hydrolysis of compound cereal liquefied enzymatic liquid was done by glucose amylase enzyme.Orthogonal test was designed based on single factor test, the best conditions for saccharifying enzymatic hydrolytic process were obtained: enzyme concentration 250 U / m L, temperature 60℃, time 60 min, natural p H, DE value reached 88.96%. The properties of PBP were measured, the content of protein and fat were 28.00, 31.10 g /100 g, respectively, dietary fiber reached 1.10 g /100 g, there were soluble and nutrient components abundantly.At the same time arsenic was 0.10 mg / kg, Pb content was less than 0.10 mg / kg, the harmful substances conformed to the national standards.