Built-in roof drainage mechanism

The invention relates to the field of building drainage, and particularly discloses a built-in roof drainage mechanism which comprises a gutter and a water collecting well, a drainage pipe is connected to the bottom of the water collecting well, a collecting pipe is connected between the gutter and the water collecting well, a water collecting bin is connected between the gutter and the collecting pipe, a partition plate is fixedly connected in the water collecting bin, and a through hole is formed in the partition plate. A sleeve is erected in the penetrating hole of the partition plate, a gap is formed between the sleeve and the wall of the penetrating hole, and a lifting rod penetrates through the sleeve. The upper end of the lifting rod is fixedly connected with a floating ball located above the partition plate, the lower end of the lifting rod is provided with a balance weight structure located below the partition plate, and the projection of the floating ball on the partition plate covers the through ho