The utility model discloses a front-mounted flue gas-denitration dust pre-removing device comprising a tank body, wherein the lower side of the tank body is provided with a flue-dust retainer, both sides of the tank body are provided with an inlet end and an outlet end, and a baffle plate is arranged in the tank body. The front-mounted flue gas-denitration dust pre-removing device is characterized in that the baffle plate comprises three baffle plates with cross sections in an included-angle shape, the three baffle plates are longitudinally arranged in a triangular shape, and the top of the outer side of the included angle of each baffle plate is opposite to the inlet end. In the front-mounted flue gas-denitration dust pre-removing device, one innovation is that the three baffle plates with the cross sections in the included-angle shape are arranged and are distributed in the triangular shape. The arrangement in the triangular shape is beneficial to improving dust removing efficiency and can not increase resistance losses overmuch.