The horizontal point was determined by the single factor test of the amount of hot water, soaking time, cooking time, and amount of cold water. Three levels of orthogonal test about four factors were designed. The optimized pretreatment conditions for the highest utilization rate of starch were as follows: 60% hot water, 24h of run food time, 80 min of steaming time, and 30% cold water, under which condition, starch utilization rate could reach 84%.