VO2(B) nanobelts were grown by a vapor transport and condensation method in a furnace and identified by standard electron microscopy methods. A phase transition process from VO2(B) to VO2(M1) was made possible under electron beam irradiation. To identify the phase transition, the variations of the phase and diffraction pattern were recorded for the VO2 nanobelts. A method to monitor the temperature of the samples in the transmission electron microscope under a certain electron beam convergence was proposed. A mesa made of the VO2 phase change material can be employed to monitor the elevated temperature in the area where the electron beam is converged.