The invention discloses a mining underground roadway blocking device. The mining underground roadway blocking device comprises a water filling device which is matched with the shape of the cross section of an underground roadway after water filling and is used for filling and blocking the underground roadway; the water filling device forms a shape matched with the shape of the cross section of the underground roadway after being filled with water, accordingly, the space of the underground roadway is filled and plugged, and the construction time of an existing anti-explosion air-tight wall is greatly shortened; and integral blocking of the underground roadway is achieved through the single water filling device of the integrated structure, the labor intensity of workers is relieved, the safety is improved, and the blocking effect is more ideal. Furthermore, the mining underground roadway blocking device is reasonable in structure, small in investment and easy to operate, only the water needs to be poured into a water filling long bag, the working efficiency is improved, cost is reduced, and the safety in the disaster relief process can be effectively ensured.