The paper aims to change the mode of manual capacitor loading and improve the automation degree and efficiency of capacitor loading. SCARA robot was selected to replace the manual mode and carry out trajectory planning to avoid motion impact affecting the stability and accuracy of capacitor loading. The structure of SCARA robot and the process of capacitor loading were introduced, and then the trajectory curve was constructed with five non-uniform b-spline curves. Finally, a genetic algorithm with penalty function was proposed to realize the trajectory planning process of robots with optimal time. The simulation results showed that the robot loading was shorter and the motion was smooth without impact, which verified the effectiveness of the algorithm. The trajectory planning method can meet the actual production requirements and improve the quality and efficiency of capacitor handing and loading.