Basement waterproof structure and construction method

The invention discloses a basement waterproof structure. A leveling layer is laid on the garage body, an SBS modified asphalt waterproof coiled material is laid at the top end of the leveling layer, the drainage plate is laid at the top end of the SBS modified asphalt waterproof coiled material, a first geotechnical cloth is laid at the top end of the drainage plate, a U-shaped drainage groove is laid at the top end of the drainage plate, and a second geotechnical cloth is laid at the top end of the U-shaped drainage groove. A first geotextile is laid on the outer wall of the U-shaped drainage groove, a second geotextile is laid on the outer wall of the U-shaped drainage groove, the first geotextile and the second geotextile are convenient to lap joint, the top end of the U-shaped drainage groove is fixedly connected with a breathable observation pipe, one end of the U-shaped drainage groove is communicated with a Z-shaped siphon, one end of the sewer well is communicated with a connecting pipe, one end of th