The effect of six different harvest time on yield and output of maize in cold-humid region of Jilin province was studied using ’Jidan 27 ’with mid-early maturity, ’Xianyu 335’ with middle maturity, ’Jidan 618 ’with mid-late maturity as materials.The results showed that the optimum harvest time are October 5 to October 15 for ’Jidan 27 ’,September 30 to October 15 for ’Xianyu 335 ’,October 5 to October 15 for ’Jidan 618 ’,the yield and output value would be the best during this time.