In view of the shortage of mechanized harvesting equipment for rapeseed stalks, a gantry electric-driven rapeseed stalks harvester was designed to realize the functions of cutting, clipping, conveying, collecting rapeseed stalks, with remote control and self-propelled across the box. The design scheme of the whole harvester was expounded, and the vertical rotary clamping cutting device was designed with emphasis, and the structural parameters of the crop divider, the cutter and the clipping and throwing rollers were determined. Through the mechanical and kinematic analysis of the clamping and throwing process of the cutting table, the influencing factors of the cutting and clamping and throwing transportation of the rapeseed bolt were clarified, and the structural and kinematic requirements of the cutter and the clamping and throwing rollers were determined. The rapeseed stalks harvest test bench was set up, and the single factor experiment and orthogonal experiment were carried out with the cutting effect and conveying effect as the evaluation indexes. The results showed that the comprehensive harvest effect was the best when the cutting knife speed was 234r/min, the clipping and throwing rollers speed was 120r/min, and the feeding speed (machine forward speed) was 0.56m/s. The field harvest verification test showed that the harvesting efficiency of the harvester could reach 0.41hm2/h, the comprehensive cutting effect was 95.6%, and the comprehensive conveying effect was 95.2%, which met the requirements of rapeseed stalks harvesting. The research result can provide reference for the structural design optimization of rapeseed stalks mechanized harvesting equipment.