Water drainage structure for side wall of center gutter and construction method for water drainage structure

The invention relates to a water drainage structure for a side wall of a center gutter and a construction method for the water drainage structure. The water drainage structure comprises a guide plate which is laid above a waterproof layer of the side wall of the gutter, a thermal insulation layer which is laid above the guide plate, a concrete protective layer which is formed on the inner wall surface of the gutter by pouring and a concrete surface layer which is poured on the concrete thermal insulation layer, wherein the guide plate is arranged towards the gutter in a slope-finding mode; a guide tube is buried in the concrete protective layer; and one end of the guide tube is positioned at the lowest part of the guide plate, and the other end of the guide tube extends out of the concrete protective layer and is positioned in the gutter. The invention provides the water drainage structure which is formed on the side wall of the gutter and is hidden between the thermal insulation layer and the waterproof layer; the water drainage structure is used for directly exhausting water after collecting and draining the water, so that the concrete protective layer is prevented from being impacted by water flow or corroded by hydrops, thereby ensuring a good using function of a roof.