Aiming at the problem of poor stationarity of robot end motion in the process of complex shape shrub pruning, an improved cubic B-spline trajectory fairing algorithm based on double tangent vector continuity was proposed. Firstly, the transition model of linear trajectory corner was established. The tangent vector constraint of connecting point was constructed by using the local properties of B-spline curve, so that the initial unsmooth pruning trajectory can be G 2 continuous after fairing. Secondly, the transition curves of planar multi-segment trajectories under different fairing algorithms were constructed. Through comparison and analysis, under the same approximation error, the curvature extreme value of the transition curve constructed by this algorithm was 40.5% lower than that of the traditional arc transition algorithm. Compared with the traditional cubic B-spline transition algorithm, the curvature of the transition curve constructed by this algorithm was more continuous and the overall fairing effect was better than that of the traditional cubic B-spline transition algorithm under the same approximation error. Finally, in order to verify the fairing effect of the algorithm on spatial pruning trajectory, a 5-axis joint robot model was established for duck-shaped trajectory pruning simulation experiment. The results showed that the algorithm can increase the extreme velocity at the end of the robot by 13.5%, reduce the extreme acceleration by 86.9%, and make the joints of the robot move more smoothly. The results verified the feasibility and effectiveness of the algorithm in the fairing of complex pruning trajectories.