Abstract: Abstract：Rice is one of the major food crops in the world, weeds are one of the main reasons for the decrease of rice yieldand quality. In traditional agriculture, the main weeding method is to use herbicides, which would not only cause environmentpollution, but also cause weed resistance. At present, mechanical weeding, as a green weeding method, is a new technology,because of the possibility of seedlings injury, it is still in the development stage. In order to avoid seedlings, there is a lagbetween the adjustment of weeding components and the movement of fuselage. During the rectification period, the weedingcomponents will inevitably cause damage to rice seedlings. Therefore, it is necessary and urgent to realize intelligent seedlingavoidance control technology by perceiving the curvature degree of rice rows, differentiating the operation path of weedingcomponents. To reduce the seeding injury rate of mechanical weeding, on the basis of obtaining the information of riceseedling belt, a control system for weeding alignment in rice field based on linear active disturbance rejection control isdesigned in this paper. Row alignment technique is a method to control the deviation of weeding component on the operationpath. By using the structure of inner and outer sliding beams, the weeding component can avoid seedling and control weedingin the working path through the row alignment mechanism. A hydraulic control system is proposed and simulation is carriedout by combining Amesim with Matlab. The simulation platform of hydraulic control system is constructed, and the controlleris designed. The simulation comparison between the linear active disturbance rejection control (LADRC) algorithm and PIDalgorithm is carried out. The results of simulation show that the line alignment time of LADRC system is 0.1s less than that ofPID system, and in the case of disturbance, the anti-interference of LADRC is better than PID control algorithm and hascertain robustness. To verify the actual performance of the LADRC, field experiments are carried out. The results show thatthe traveling speed and working depth have a significant impact on the seeding injury rate, and the adjusting space has a mildimpact. The optimal working parameters combination is that the traveling speed is 0.5 m/s, the adjustment space is 60 mm, theworking depth is 20 mm,, and the seeding injury rate is 3.6%. As the performance comparison experiment shown, the averageseeding injury rate with alignment control system is 3.9%, while the average seeding injury rate without alignment controlsystem is 18.6%. The system can meet the requirements of mechanical weeding control, and can provide references for theprecise control problems in paddy field environment.