Biaxial geogrids are a kind of high strength geosynthetics which take high molecular polymer as main raw material, and add the additives of anti-ultraviolet radition and anti-aging; Then through directional stretch, original scattered chain molecule is realigned at linear state. According to physical characteristics of high molecular polymer, under the condition of certain temperature control, plastic geogrids are stretched at certain direction, so they have high tensile strength at this direction. Their tensile strength is 100-200 Mpa and elongation is only 4-10%, which nearly approach the level of mild steel and they have much advantage over traditional and present reinforcement materials. So they are a quite ideal geosynthetics for strengthening civil engineering and reinforcing road base.