Geocomposite drainage is created by bonding two layers of geotextile with geonet, which combines the filtration property of geotextile and the drainage and protection properties of geonet. Thus providing a complete “inverted filter-drainage-to-protect” effect. Drainage geonet core is extruded by high-performance HDPE resin, adding carbon black and ultraviolet and antioxidant stabilizer. The interlaced net forms into a drainage channel which has good vertical drainage properties.