Aramid fiber is a new high-tech synthetic fiber, which has excellent properties such as ultra-high strength, high modulus, high temperature resistance, acid and alkali resistance, light weight, etc. Its strength is 5-6 times of that of steel wire, modulus is 2-3 times of that of steel wire or glass fiber, toughness is twice of that of steel wire, and weight is only about 1/5 of that of steel wire. It does not decompose or melt at 560 ℃. It has good insulation and anti-aging performance, and has a long life cycle.