This paper expounds several main functions of geosynthetics and what kind of projects these functions are mainly embodied in.

1) filtration: As a filtration layer, geosynthetics are laid in the seepage outlet area, which, like the traditional gravel filtration layer, can improve the impermeability strength of the protected soil.

2) Drainage: Geotextile with a certain thickness has good three-dimensional water permeability, which can quickly drain water through the plane of geosynthetics in the horizontal direction and form a horizontal drainage layer.

3) Isolation: In general road construction, subgrade, subgrade materials and general materials are mixed together, which weakens the original design strength, drainage and filtration functions. In order to prevent this phenomenon, geosynthetics can be placed between two materials with different characteristics, so that they will not be mixed together, but maintain a unified function.

4) Seepage prevention: Geomembrane and composite geosynthetics can prevent liquid leakage and gas volatilization, and protect the safety of the environment or buildings, such as seepage prevention of dams and reservoir areas.

5) Protective function: it can protect soil or water body, prevent the river bank or coast from being washed away, and prevent the soil from freezing.

6) Reinforcement: provide tensile strength for soil and reinforce soil slopes, dams, foundations and retaining walls.