A dual circle tangential line-tracking control method was designed to solve the problem of linear tracking control when navigation system of 2BFQ—6 type direct-seeding combined dual purpose planter for rapeseed working near the boarders of a field. Firstly, a geometric relation formula of optimal connecting linkage was found by quantitative analysis of the far targeted line searching path. Then the method of dual circle tangential line-tracking was constructed by the geometric relation formula, which created decision-making. According to the position and orientation of the tractor, the matching control equations were selected by decision-making, and its calculations were used for tractor navigation control. Hence, a navigation system simulation model was established, which was used to achieve the purpose of optimizing model parameters and verifying the model performance. Path experiments were carried out with the navigation system of tractor. Experiments result showed that the overshoot of lateral deflection error response was less than 3%, rising time and settling time of the response were smaller than 14s and 19s, respectively. When the speed of tractor was 0~7m/s, the initial lateral deviation error of the tractor center between the target line was 7m and the initial course deviation error was 90°. When it was compared with the method of conventional pure pursuit navigation model, the dual circle tangential line-tracking control method resulted in less values of overshoot and settling time. Based on the results of path tracking experiments and field experiments, the dual circle tangential method could be applied to operation of lane-changing and turning of 2BFQ—6 type direct-seeding combined dual purpose planter for rapeseed.