Based on the design ideas of using lowspeed doubleacting knives to achieve opposite cutting, optimizing the structure of knives to avoid excessive impact on the filaments, and segmenting the cutting operation to avoid multiple cutting of the filaments, a double-acting opposite direction cutting end effector was designed to be installed on the safflower harvesting machine. A double-acting opposite direction cutting end effector on the safflower harvester was designed to achieve automatic harvesting and low loss harvesting of the filaments while guaranteeing the net rate of filament removal. By establishing a tool-filament cutting mechanics model, the key factors affecting the cutting and damage of the filaments were clarified as the tilt angle of the cutting edge, the tilt angle of the cutting edge, and the feeding speed of the cutting edge. By analyzing the conditions for the filaments not to slip for the cutter, the causes of cutting resistance of the cutting edge were investigated from the microscopic point of view, and the optimum ranges of the cutting edge tilt angle, cutting edge inclination angle and cutting tool feed speed were obtained based on the ultimate cutting stress calculation analysis and the previous safflower cutting tests in the laboratory. According to the motion state of the end effector, the harvesting operation was divided into four working sections: cam start section, cutting and separation section, cutter stop section, and cutter return section, and the cutter motion trajectory in each working section was clarified. To improve the working performance of the double-acting opposite direction cutting end effector, a three-factor, five-level quadratic orthogonal combination test was conducted with cam speed (cutter feed speed), edge tilt angle and cutter blade inclination angle as test factors, and filament removal rate and filament broken rate as evaluation indexes, and the test results were analyzed by using Design-Expert software to clarify the effect of each test factor on the indexes. The best combination of parameters was obtained with cam speed of 27.9r/min, inclination angle of the cutting edge of 16.1°, and inclination angle of the cutting edge of 19.7°, which corresponded to filament removal rate of 91.78% and filament broken rate of 5.32%. The optimal combination of parameters was used to validate the end effector in field test, and the validation results showed that the net filament removal rate was 91.25% and the filament broken rate was 5.57%, with error no more than 5% from the optimized results, indicating that the double-acting opposite direction cutting end effector can better accomplish the harvesting operation with high net filament removal rate and low broken rate under this combination of parameters. The research result can provide a theoretical basis and technical reference for mechanized harvesting of safflower to achieve high efficiency and low loss harvesting, which had important significance and application value.