The invention discloses a condenser washing device for an open type circulating water system. The condenser washing device comprises a water source of a river, a lake or a sea and a condenser cooling water system. The water source of the river, the lake or the sea enters through an inlet of the condenser cooling water system and returns back to the river, the lake or the sea after flowing through a heat exchanging pipe of a condenser. The heat exchanging pipe is internally provided with a washing guide device. The washing guide device comprises a base, a plurality of blades and a cone. The multiple blades are fixedly arranged on the base at equal angle intervals, the narrow ends of the multiple blades are fixed to the bottom of the cone, the other ends of the blades are fixed to the bottom of the base, the base is fixed into the heat exchanging pipe, and the head part of the cone is right opposite to the cooling water coming direction. The invention discloses the washing guide device. The condenser washing device and the washing guide device have the beneficial effects that as sand in natural water is used for constantly washing the condenser heat exchanging pipe online, the cost is extremely low, and the washing effect is remarkable.