In view of the lack of corresponding ear harvesting machines for domestic seed corn, the high labor intensity of seed corn harvesting, and the existing corn harvesters’ inability to meet the requirements of the use of technical indicators such as ear loss rate and landing kernel loss rate, a corn ear harvester with middle-stretched stem cutting handle, flexible ear picking and rapid seed clearing of seed corn was designed. The structure and working principle of the whole machine were briefly described, and the key components were theoretically analyzed, calculated and selected. In order to verify the reliability and practicability of the machine performance, field tests were carried out. Taking the rotation speed of the pulling stem roller, the forward speed, and the speed of the trash exhaust fan as the test factors, the three-factor three-level orthogonal experiment was carried out based on the performance index of the loss rate of ears and the loss rate of landing kernels, and the range analysis and variance analysis had a significant impact on each factor. The optimal parameter combination was selected for each test factor: the forward speed was 4.83km/h, rotation speed of the pulling stem roller was 788r/min, and the speed of the trash exhaust fan was 1200r/min, the ear loss rate was 1.83%, and the landing kernel loss rate was 1.01%. The corresponding parameters were tested and verified, and the results of the verification test were obtained: the loss rate of ears was 1.85%, and the loss rate of landing kernel was 1.01%. The optimization results were basically consistent with the verification test results, and the prediction model was reliable. The operating performance of the whole machine met the technical requirements of seed production corn ear harvesting.