Composite geotextile refers to two cloth one membrane anti-seepage geotextile or one cloth one membrane anti-seepage geotextile, also known as composite geotextile, widely used in projects such as reservoirs, artificial lakes, and landfill sites; HDPE geomembrane refers to high-density polyethylene plastic film, which has the characteristics of anti-seepage and isolation. The difference between composite geotextile and HDPE geotextile is that composite geotextile is a new composite geotextile material composed of geotextile and geotextile, while HDPE geotextile is a simple plastic film, but both have impermeable properties. In some relatively strict projects, such as landfills, composite geomembranes are used, and of course, the two are also used in combination.