Abstract: Based on the self-designed biped climbing robot, named Climbot, an energy-optimal motion planning method is proposed, which considers the kinematics and dynamics constraints simultaneously. Energy consumption for climbing is firstly described by a mathematical model. Then an energy-optimal motion planning method is proposed which contains the joint trajectory planner at lower level, the path planner at upper level and a searching algorithm for optimal path. The effectiveness of the energy-optimal motion planning method is demonstrated by practical example of Climbot, and detailed analysis of the result is provided as well. The result proves the effectiveness and feasibility of the proposed motion planning method.