The problems associated with loading capacity need to be settled urgently before sophisticated applications of hexapod robots. Ground reaction forces acting at the feet of supporting legs determine the joint moments of each leg and counteract external and inertial forces and moments of the robot to keep balance. An efficient approach for optimizing the foot force distribution is proposed to improve the loading capacity of hexapod robots with the insect-mammal mixed tripod gait. Force and moment equilibrium equations are combined with suitable constraints for obtaining a solution of foot forces, which will minimize joint moments and increase the loading capacity of hexapod robots.