Abstract: In order to shorten the saccharification time of corn crude starch for production of corn syrup and improve its sacchrification, the influence regular of the parameters of the extruding-liquefying system on main observed indexes of syrup was studied by means of the experiments in the laboratory. These parameters were the barrel temperature, moisture content of the corn crude starch, screw speed, dosage of high temperature resistance α-amylase added during the process of liquefying and saccharifying. The main indexes included the filtration speed of syrup, the dextrose equivalent of syrup and the available ratio of starch. Research results indicate the dextrose equivalent of syrup, the filtration speed of syrup and available ratio of starch are respectively 95.5%～96.3%, 163.2～177.3 L/(m²·s) and 94.2%～94.4% under the conditions of optimum parameters of extruding-liquefying system. Saccharifying time under the optimum conditions is 18 h shorter than that under the traditional ones.