Reverse drainage blocking structure of external drainage skylight

The utility model relates to a reverse drainage blocking structure of an external drainage skylight, which comprises a drainage port arranged at a corner of a skylight frame and communicated with a front drainage groove of a skylight front frame and/or a side drainage groove of a skylight side frame, and is characterized in that a rotating shaft seat groove is formed above the drainage port on the outer side of the corner of the skylight frame; and the lower part of the rotating shaft is connected with a baffle plate which corresponds to the outer side of the water outlet. The baffle is additionally arranged at the position of the water outlet, the baffle correspondingly blocks the outer side of the water outlet, the baffle is limited to be opened in an outward rotating mode through the rotating shaft on the baffle, water is drained from the inner side to the outer side, reverse water drainage from outside to inside cannot be achieved, and the stability of the water drainage performance of the skylight is eff