The utility model discloses a cogongrass steel construction roofing eaves mouth structure, including cogongrass roofing body, this cogongrass roofing is by the lining to being heat preservation cotton layer, cement sheet layer, waterproof layer, cement welt protective layer and emulation cogongrass tile layer outward in proper order, this has internally offered embedded gutter at this cogongrass roofing, its characterized in that: lay one row of cogongrass on the edge of gutter ridge one side, the emulation cogongrass tile layer of laying on the head of this row cogongrass and the cogongrass roofing body is folded mutually and is fixed, inside the free curtaining of afterbody to the gutter of this row cogongrass. Install special -shaped personal letter grass on the edge of gutter eave one side, the holding strip is arranged in cogongrass middle zone position to this dysmorphism personal letter grass, encorbelments in installation back both sides, and ridge direction overhang length was as the criterion in order to cover the gutter opening, the eave direction passes through naturally, forms harmonious whole with the eave grass. It can compromise service function and pleasing to the eye requirement simultaneously, has reduced the cost.