This paper proposes an optimization design method for spacecraft formation reconfiguration aimed at target switching in the Taiji mission, with the effectiveness of the method validated through simulations. Initially, a dynamic model for formation reconfiguration is developed, and the principles for constructing equilateral triangle formations and the associated impulsive maneuver model are outlined. Subsequently, an optimization approach is introduced for the target switching mission, incorporating constraints such as reference orbit variation and formation scale adjustment. Numerical simulations are conducted to assess the proposed method, with results confirming both the accuracy and optimality of the model. The findings demonstrate that the proposed method successfully meets the target configuration design requirements and produces optimal results. Furthermore, variations in the reference orbit significantly affect the orientation of the formation plane, leading to rotations along the Y-axis of the LVLH coordinate system or the symmetry axis of the formation’s own plane. Mission fuel consumption is found to vary with both mission duration and the prime phase angle. This research addresses a gap in the design of target configurations for spacecraft formation reconfiguration in space-based gravitational wave detection missions and provides a valuable reference for optimization design in similar future missions. Future work will involve incorporating more complex constraints and exploring multivariable optimization techniques to enhance the generalizability and flexibility of the design.