This article is focused on a double-arm and double-manipulator live working robot. The arm motion of the robot for insulator string replacement during the operation process was decomposed. The basic operation dynamic model was established by the Lagrange method combined with the armature voltage equation, the dynamic equations of manipulator 2 were calculated, the manipula-tor motion trajectory planning method was proposed based on five-polynomial interpolation, and the kinematics equations of manipulator 2 each joint were calculated. Robot manipulator dynamics and kinematics simulations were performed in ADAMS environment. The re-sults verify the correctness of the dynamic model, and the joint trajectory planning meets the kinematic requirements. Finally, insulator string replacement experiments of the robot were tested on actual line. The results show that each robot manipulator joint movement ob-tains a better dynamic performance, which validates that the proposed five-polynomial interpolation manipulator trajectory planning has strong practicability, and can further improve the robot operational efficiency and stability.