Abstract: In order to solve the in-situ measurement of high-temperature phase transition of micro-nano films (< 10 μm thick) on the substrate, in the present work a self-designed heating sample stage and the grazing incidence X-ray diffraction mode of a commercial X-ray diffractometer were skillfully combined, and thus a novel in-situ measurement method of high-temperature phase transition of micro-nano films was proposed.The characteristics of temperature distributions on the surface of the sample stage and the micro-nano films were investigated, and the temperature control effect of the in-house fabricated heating sample stage was hence verified.Finally, the X-ray diffraction (XRD) patterns of the micro-nano vanadium dioxide (VO₂) films at different temperatures were obtained and the high temperature phase transition of micro-nano VO₂ films was clarified.