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Mechanical weeding method has obvious advantages during the ridge tillage of soybeans production in Northeast China, such as preemergence weeding can break soil consolidation and raise ground temperature to ensure orderly emergence of seedlings, the postemergence weeding can loosen the soil between plants, eliminate young grass between plants, store water and conserve moisture, and then promote the growth and development of soybean. In addition, the application rate of herbicide is effectively reduced by mechanical weeding which can alleviate the high dependence of current agricultural production on herbicide. 3ZCF-7700 multifunctional weeding machine could meet the agronomic requirements of scarifying and weeding in intrarow for corn, soybean and other crops. However, it was not suitable for weeding in the field with many crop residues and stems. Therefore, the weeding monomer mechanism was improved to solve the problems of poor adaptability, complicated structure and unadjustable lateral spacing of the front and rear combtooth drive discs. For the problems of comb teeth are easy to wind grass and clogging, weak ability to stable into the soil during the intrarow weeding, the planetary gears combtooth intrarow weeding mechanism was designed and its main parameters were determined. According to the index of weeding rate and injury seedling rate, the main factors of operation performance and the value range of each factor were obtained by single factor experiment in the selfmade indoor test bench. And then, the orthogonal test was carried out in soybean field to investigate the influence of test factors on the work performance of weeding mechanism by the combtooth angle, the deepest soil position of the comb teeth, and the deepest soil depth of the comb teeth was taken as the experimental factors. The results showed that the order of the factors affecting the weeding rate from primary to secondary was the deepest soil depth of the comb teeth, the deepest soil position of the comb teeth and combtooth angle, and that affecting the injury seeding rate was combtooth angle, the deepest soil depth of the comb teeth and the deepest soil position of the comb teeth. The optimal horizontal combination was 10° of combtooth angle, 80mm of the deepest soil position of the comb teeth, and the deepest soil depth of the comb teeth was 47.5mm. And then five field verification experiments were carried out with the optimal horizontal combination. The average result of the data was 86.3% of weeding rate and 2.66% of injury seedling rate between plants, which showed a stable work performance. The study provided guidance for the design of reliable soybean intrarow weeder.