Building roof cornice waterproof device

The utility model relates to the field of building waterproofing, in particular to a building roof cornice waterproof device. The building roof cornice waterproof device comprises a shell, a filter assembly and a water storage assembly, a filter screen in sliding connection is mounted between a mounting groove and a limiting groove, two fixedly connected scrapers are mounted at one end of the shell, and the filter screen is located between the scrapers. According to the building roof cornice waterproof device, rainwater falls into the outer shell along the cornice, at the moment, the filter screen can obstruct impurities such as fallen leaves in the rainwater, the impurities such as the fallen leaves are left on the filter screen, the motor is started to drive the lead screw to rotate, the filter screen can be driven to move in the rotating process of the lead screw, and therefore the fallen leaves are prevented from falling off. In the process that the filter screen moves towards the scraping plate, the scra