The preparation process of polyimide fiber includes the following steps: 1. preparing polyamic acid solution as the spinning precursor through polycondensing maleic anhydride monomer and diamine monomer; 2. dry spinning to prepare polyamic acid fiber; 3. imidating polyamic acid fiber to form polyimide fiber; and 4. hot stretching polyimide fiber at 350-470 deg.c for 3-8 times. Thus prepared polyimide fiber has high strength, high modulus, high heat resistance, high chemical corrosion resistance and relatively high limiting oxygen index, and may be used widely as reinforcing material of composite material and cable, rope for vehicle and ship, filter material, etc. |