Abstract: OBJECTIVE To probe into the thermal property，the mechanism of the thermal decomposition and the prospective lifetime of cefodizime disodium (CDZ). METHODS The thermal decomposition of CDZ was measured by thermogravimetry (TG) and differential scanning calorimetry(DSC)，the IR spectra of CDZ and its remainders from thermal decomposition at various temperatures were determined, the molecular bond orders were calculated by GAMESS method of quantum chemistry, the kinetics parameters of thermal decomposition of STVD were obtained by thermogravimetry and the prospective lifetime of CDZ at different temperature was speculated by Dakin equation. RESULTS The results indicated that the thermal decomposition of CDZ was a multi-stages process. The kinetic parameters, such as activation energy Ea=173.9 kJ·mol-1, pre-exponential factor A =1.175×1017 min-1 in N2, and Ea =172.3 kJ·mol-1, A =2.692×1017 min-1 in air，were obtained. CONCLUSION The thermal property of CDZ is quite stable in the routine temperature.