To address the increasing cleaning blind zones when the underwater cleaning robot works in the anode block area, this paper proposes a path planning methodology specifically designed for cleaning robots equipped with unilateral nozzles. By analyzing the spatial relationship between the robot and anode blocks, a hybrid motion path integrating linear and curvilinear segments is developed, accompanied by derived geometric constraints to prevent collisions with cleaning blind zones. Simulation and experiment results demonstrate that the proposed approach effectively maintains safe operational clearances while achieving complete anode surface coverage, providing a reliable technical framework for underwater robotic maintenance in constrained marine environments.