Aiming at the problems of irregular ditching and uneven force of the cutters used in the current tobacco planting process, this paper designs a special ditching cutter for the tobacco planting ditch fertilizer machine. In order to make the cutter force uniform and labor-saving, the line segment ratio and included angle of the ditching tool ridge curve (second-order Bezier curve) are the changing factors. The parameters of the ditching tool are optimized through EDEM simulation analysis, and the current ridge curve line segment is obtained through EDEM simulation analysis and field test verification. The ratio is 1:3, when the included angle is 150°, the uniform force of the ditching tool is the best and it can open a groove with a preset width of 100mm and a depth of 100mm (adjustable depth), and the ditching pattern is regular and stable.