The fundamental pictures of phase transitions in a variety of materials remain blurry and difficult to fully elaborate. For instance, the nature of metal insulator transition (MIT) process in VO2 have been wildly investigated. The MIT in VO2 occurs when the atoms in the metallic structure dimerize and break the crystal symmetry, resulting in a shift from a tetragonal rutile phase to a low temperature monoclinic phase. In this work, within a framework of thermoelectric transport measurement, we studied the electronic entropy changes during the phase transition and found giant electronic entropy changes are according for the total energy involved. In my talk, I will detail the experiment and try to establish a general explanation for this kind of MIT transitions.