Abstract: By calculation of the title compound molecules, the geometric structure, spectra and thermodynamic properties of 2,5-Bis (4-methylpheny)-1,3,4-Oxadiazole molecule were investigated at B3LYP/6-31+G* level by applying the density functional theory. The result showed that the three rings of the said molecule were coplanar, which is consistent with the crystal structure. In gas phase, the absorption peak of the lowest energy transition detected was at 315 nm, corresponding to the electron transition of π－π* from HOMO to LUMO. Thermodynamic calculations showed that, with temperature rise, the standard molar enthalpy, standard molar heat capacity and standard molar entropy of the title compound molecule underwent an increase characerized by a quadratic function. The standard molar enthalpy and standard molar free energy were -102.51 kJ/mol and 110.88 kJ/mol under standard atmospheric pressure and 298.15 K, respectively. The finding indicate that although heat relaesse exists in the process for a stable element being transformed into a tilte compound, the release is not all spontaneous.