Abstract: The polymerization processes of bis[4-(4-ethynylphenoxy)phenyl] sulfone and its polymer's dynamic mechanical properties were investigated by torsional braid ana-lysis(TBA) and infrared spectroscopy. Results showed that the multiple transitions including the melting, low-and high-temperature reaction of oligomer, glass transition and decomposition reaction of its polymer could be characterized in the TBAspectra. The glass transition temperatures of its polymers depend upon the conditions of polymerization.