Through the research analysis of corn harvester status at home and abroad as well as market demand of the current corn harvester，a new type of corn harvester for the stalk chopping and conveying device reaping both corn stalk and spike were designed emphatically. The advantages and disadvantages of different types of cutter were compared and analyzed, the cutting performance and function of feeding were considered, then the rotor milling cutter was adopted as the stem cutting device. To explore the power consumption influence factors of rotor milling cutter, the 3D simulation software ANSYS/LS-DYNA was used and a threefactor and threelevel orthogonal simulation test of the rotor rotating speed, thickness and the blade angle was carried out. The simulation results showed that the rotational speed and blade angle on the level of P≤0.10 had significant effects on power consumption for corn stalks cutting, and the thickness of the blade on the level of P≤0.10 had less influence however. Through the simulation, the best working parameters of rotor milling cutter was determined as the blade speed of 1400r/min, thickness of 7mm and blade angle of 20°, and on this occasion the power consumption was minimum. The single stem feeding device and double stem feeding device were compared and analyzed, and the transmissions were considered in as well, the transmissions of single stem feeding device were simpler. Then different tooth profiles and different speeds of roller conveyors were designed, and the relationship between four conveying rollers linear velocity was established by theoretical analysis, providing basis for transmission design. The different types of stem cutter were compared and analyzed, and rotary chopper was adopted. Then the drum diameter, blade installation form, dynamic location were designed and calculated, and through calculating, the theoretical length of stalk chopped was 34.6mm. Finally, the field experiment was carried out. Results showed that the feed rate was 4.06kg/s, operation speed was 1.2m/s, and the average stubble height was 9.5mm, coefficient of variation was 6.32%. The stem length curve was drawn, and the actual chopped stalks length was between 0 ~ 40mm and percent of pass was 95%. The average real chopped length was 35.2mm and had no significant difference with the theory chopped length 34.8mm in the level of P≤0.05. At the same time, the other indicators of the harvester meet the design and relevant national standards.