Abstract: Weed damage is one of the main reasons leading to the reduction of rice yield and quality. The elastic tooth pulling weed control can not only effectively remove weeds between rows and plants, but also solve the problem of weed mechanical control in the near root zone of rice. At present, it has become the main technology of mechanical control of weed damage in rice field. However, the existing tine operation process does not distinguish between rice and grass growth areas, and uses constant operation parameters and the same structural parameters, which makes it difficult to take into account the weeding rate and seedling injury rate at the same time in the operation process, so it is urgent to further study the technique and equipment of tine seedling protection and weeding. The methods of protecting seedlings and weeding in elastic toothed paddy field are mainly classified as operation parameter optimization, structural parameter improvement and operation mode innovation. The optimization of operation parameters is currently the most widely used way of protecting seedlings and weeding with elastic teeth, but the optimal operation parameters obtained are only suitable for the current rice field environment, and the method of protecting seedlings and weeding is lack of universality. In terms of structural parameter improvement, take the elastic tooth weeding as an example. At present, the operation process of the elastic tooth swing type rice field weeder does not distinguish between seedling and grass growth areas. The improvement of the elastic tooth structure is restricted by the injured seedling rate, and the space for improving the weeding rate is limited. As for the innovation of operation mode, facing the complex environment of paddy field and the dense planting conditions of rice, there are still technical bottlenecks in the accurate division of rice grass growth area by conventional perception methods such as vision and laser, and the effective method of fast switching operation mode between seedling area and grass area needs to be further studied. In view of the special environment of rice field, this study proposed a method of dividing the seedling grass growth area based on tactile perception, and designed a weeding machine with variable comb and oblique tooth structure, adjustable operation depth and operation range parameters, and fast switching operation mode in the seedling grass growth area. A combination of flat pressure comb teeth and inclined swing teeth was adopted to design a rapid mode switching mechanism, and the values of the pressure amplitude and swing amplitude were determined through parameter optimization. A rice grass growing region partition perceptron was designed by using piezoelectric film sensor and bending sensor. Through data acquisition, filtering, segmentation and other processing, the rice seedling and weed growing regions were accurately divided. Based on the division results, the operation mode is automatically switched to the flat pressure comb operation mode with low seedling damage rate in the root zone of rice seedlings, and the pressure swing oblique tooth operation mode with high weed control rate in the weed growth area, so as to realize seedling protection and weed control. The field performance tests of three operation modes, i.e. the flat pressing comb, the pressure swing oblique tooth and the pressure swing switch, were carried out. The results showed that the weeding rate of the flat pressing comb operation mode was 48.69%, and the seedling injury rate was 3.47%; The weeding rate was 86.01% and the seedling injury rate was 15.84% in the press swing bevel gear operation mode; The weeding rate was 81.02% and the seedling injury rate was 4.26% in the flat pressure swing switching operation mode. Compared with the test results, the comprehensive performance of the flat pressure swing switching operation mode is the best, which can meet the requirements of rice seedling protection and weeding operation.