The invention relates to a buffering and illuminating system used for reducing impact damage on a water turbine caused by fishes passing the water turbine. The system comprises fixed guide vanes, movable guide vanes, an exhaust water pipe, buttresses and a volute, and is characterized in that the edge of an inlet of each fixed guide vane is covered by a layer of rubber, and the edge of the inlet of each buttress is also covered by a layer of rubber; and illuminating systems are arranged between the buttress at the position of the exhaust water pipe and the side wall of the exhaust water pipe, between the buttress at the position of a volute inlet and the side wall of the volute inlet, between the buttress at the position of the volute inlet and the buttress, between the fixed guide vanes and between the movable guide vanes, and the illuminating systems are all arranged at the downstream sides of the water inlet edges. According to the buffering and illuminating system used for reducing the impact damage on the water turbine caused by the fishes passing the water turbine, the injuries and deaths of the fishes passing the water turbine can be effectively reduced, and the system can be widely applied to mixed flow and axial flow type water turbines, and not only can be used in a newly-built hydropower station, but also can be used in an already built hydropower station.