Position　control　of　a　3-DOF　horizontal　underactuated　robot　is　investigated.　A　new　fuzzy　control　system　based　on　hierarchical　control　idea　is　proposed　for　this　kind　of　robot.　The　endpoint　position　control　of　this　underactuated　system　can　be　regarded　as　the　folding　or　unfolding　motion　of　the　passive　joint　and　the　rotation　of　active　joint.　The　first　joint　follows　the　predefined　trajectory,　and　then　the　second　joint　and　the　third　joint　achieve　the　position　control　based　on　the　dynamic　coupling　of　each　other.　The　control　torque　or　voltage　of　the　second　active　joint　are　determined　by　the　weighted　sum　of　the　output　parameters　of　fuzzy　control.　Using　this　control　method,　the　numerical　simulation　and　experiment　of　3R　underactuated　robot　for　the　tip　point-to-point　(PTP)　position　control　are　implemented　in　operational　space.