A method of producing corn starch by enzymatic process involving: soaking the corn; crushing the corn, separating and washing embryo; fine grinding; washing and drying fiber; separating and drying protein; washing, dewatering and drying the starch. An enzyme preparation is added before the step of washing, dewatering and drying the starch; the enzyme preparation is cellulose, or xylanase, or combination of the cellulose and the xylanase; and addition of the enzyme preparation is from 0.001% to 0.08% by weight of the corn. Based on the technology of traditional wet process, the method of the present invention comprises a step of adding enzyme preparation in the process of separating the corn, which improves the effect and the efficiency of mechanical separation, and further improves the purity and yield of the substance separated while also reducing the energy consumption.