Abstract:Chemistry & Biotechnology Research Institute, Sichuan Vocational and Technical College，Suining, Sichuan 629000,China) Abstruct: The 2-phenyl-5-(6-pyridazinon-3-yl)-1,3,4-oxadiazoles were subjected to structural optimization and calculation of frequency at B3LYP/6-31+G* level, and their IR spectrum, Raman spectrum and thermodynamic properties under different temperatures were thus worked out. The result shows that the molecules of pyridazine ring, oxadiazole and phenyl ring were on the same plane. The molecule as a whole does not have any symmetry. There exists an excellent function relation formula between the thermodynamic properties(such as the gaseous heat capacity, entropy, enthalpy) and temperature.