A mutijoint robot arm named "Moray arm" has large kinematic degrees of freedom at the arm and a powerful slider at the base, thus possessing unconventional features such as ability to enter a narrow space while avoiding obstacles. In this study, we first propose a path-planning algorithm for the obstacle avoidance control of the Moray arm. The algorithm is based on the spline interpolation technique and the graph search in work space. To guarantee the Moray arm in motion not collide with obstacles, the generated obstacle collision-free path must be tracked accurately. Thus, we then introduce a feedforward path-tracking controller for the Moray arm to track the generated path. Computer simulation was executed to show that, 1) the obstacle collision-free path for the Moray arm can be effectively generated by the proposed obstacle collision-free path-planning algorithm, and 2) the generated obstacle collision-free path can be well tracked by the Moray arm through the introduced feedforward path-tracking controller.