Abstract: Aiming at the problems of high tillage resistance, high power consumption and large amount of soil movement during the operation of the trencher of the current orchard ditching machine, a rotary trencher was designed and its structural parameters were optimized by orthogonal test. Combining theoretical analysis and empirical design, it was preliminarily determined that the range of cutting edge length of the trencher was 100-110 mm, the cutting edge width ranges was 30-50 mm and the value range of the angle of penetration was 19°-23°. The order of primary and secondary factors affecting power consumption obtained from orthogonal test were as follows: angle of penetration, width and length of cutting edge, the optimum combination were 21° angle of penetration, 40 mm edge width and 105 mm edge length. The order of the main and secondary factors affecting the cross section area of soil disturbance were as follows: angle of penetration, length of cutting edge, width of cutting edge, the optimal combination were 21° angle of penetration, 40 mm edge width and 110 mm edge length. The optimal combination of cutting edge length 105 mm, cutting edge width 40 mm and sinking angle 21° was obtained by comprehensive weighted scoring method. When these parameters combination were obtained in the field validation test, the power consumption of the trencher was 3.09 kW and the cross section area of soil disturbance was 9 531.21 mm~2, which was better than the orthogonal test results of each group.