To meet the requirements of forming complex and hard-to-bend orthodontic wires’, this paper proposes to use MOTOMAN UP6 for the bending operation and develops the finite point extension method for robotic trajectory planning. The inputs of this method are the key points including the midpoints, endpoints and the position of the offset of an orthodontic wire. The dichotomy is adopted to search the ratio of chord length to arc length and the area surrounded by the chord and arc of adjacent key points. The number and positions of the controlled points are determined accordingly based on the required accuracy. The MATLAB is applied to calculate the angle of bending at each control point from the perspective of rebound elasticity. After the control points’ message was obtained, the experiment is developed and shown that the finite point’s extension method can be used to plan the trajectory of robotic bending operation with an improved accuracy and efficiency in comparison with current manual practice.