Abstract: To address the issue of low efficiency in manual intra-row weeding for tobacco before the rosette stage, an oscillating weeding device based on the crank-rocker mechanism without quick-return characteristics was designed. This device utilized a motor-driven crank-rocker mechanism to drive the weed shovel to perform reciprocating opening and closing movements, achieving weeding and seedling avoidance. Through theoretical analysis and structural design, the motion trajectory of the weeding shovel and the operating mechanism of the seedling avoidance system were analyzed. Virtual simulation and parameter optimization were conducted using ADAMS software, with device running speed and crank speed as variables, and coverage rate and intrusion rate as the evaluation indicators. Field validation tests were subsequently conducted. The simulation results showed that the impact of the device's traveling speed on its indicators was significantly greater than that of crank speed. Under the optimal parameter combination of a device traveling speed of 0.28 m/s and a crank speed of 4.27 r/s, the weeding coverage rate was 85.78%, and the crop intrusion rate was 6.63%. The field experiment results were consistent with the simulation results, indicating that the device met the requirements for intra-row weeding for tobacco before the rosette stage, showing reliable operational performance.