The effect of comonomers acrylamide(AM)and 2-acrylamido-2-methylpropaneesulfonic(AMPS)on the preoxidation and spinnability of polyacrylonitrile(PAN)at the same time were investigated using differential scanning calorimetry(DSC)method and the reactivity ratios of AN/AM and AN/AMPS in suspension polymerization were calculated by Fineman-Ross method and Kelen-Tüd?s method.The apparent activation energies(Ea)of cyclization reactions were calculated by Ozawa method and Kissinger method.The results indicated that the stabilization and spinnability of P(AN-AM)has been remarkably improved with the incorporation of AMPS monomer compared with PAN homopolymer,such as broadened exothermic peak and smaller Ea of cyclization,which is attributed to the initiation of comonomer through ionic mechanism.