In this paper, a new path-planning algorithm is proposed based on inverse kinematics (IK) and end effector maximum mobility direction. As a fundamental tool, the IK is used in many fields, forexample, path planning. In order to find the manipulator configuration, first, a 5-DOF humanoid manipulator IK solver is obtained and verified. According to Yoshikawa’s manipulability definition, the mobility of the end effector in a desired direction can be measured. If the end effector moves along the maximum mobility direction, the motion generation efficiency in the Cartesian space is optimal. However, the maximum mobility direction is defined locally for the current configuration of the manipulator. If the start configuration and the traveling time are pre-determined, the path can be determined uniquely, and the end effector may not reach the precise goal position. Therefore, a unit direction vector is used for revising the direction and making the end effector move close to the goal position. The simulation results demonstrate the effectiveness of this path-planning algorithm.