Aiming at the problems of high missed weeding rate and low weeding rate between plants in paddy fields, and the existing weeding device cannot determine the position of the seedlings and led to the high seedling damage rate, an arc-tooth type automatic seedling avoided weeding device was designed to remove weeds between plants during paddy field cultivation, which was based on the idea of controlling the intermittent opening and closing movement of the weeding execution component. According to the growth status of rice plants in the weeding period of intertillage, the symmetrical weeding teeth used to remove weeds between plants were designed through theoretical analysis, and the main structural parameters of arc-shaped weeding teeth were determined. The automatic control system for avoiding seedlings was designed through the synergy of photoelectric sensors and electric linear actuators. When the weeding device needed to perform the action of avoiding seedlings, the control system controlled the arc-shaped weeding teeth to open a certain distance according to the real-time monitoring of the forward speed to avoid the seedlings. A virtual experiment was carried out based on the dynamic simulation software LS-DYNA. In the experiment, the soil disturbance rate within 0~40mm below the ground surface was used as the evaluation index, and the working depth of the arc-shaped weeding tooth of the device was determined to be 32mm, and at this time, the soil disturbance rate reached the maximum value, which was 90.02%. The operating performance of the inter-plant weeding device and automatic seedling avoidance control system was verified through field experiment. When the forward speed was 0.5~0.9m/s, the average weeding rate of the device was 86.51% and the average seedling damage rate was 0.20%. The performance of weeding and seedling avoidance was stable, and the operation quality can meet the agronomic requirements of paddy field weeding and the operation requirements of “avoiding seedlings and weeding” between plants.