A new transparent Tm3 -doped ZrF4-based nanocrystallized glass with the composition of 55ZrF4-20BaF2-18.8YF3-5AlF5-1.2TmF3 (mol%) (ZBYA) has been prepared by a conventional melting quenching technique and the subsequent heat treatment processes. The glass characteristic temperatures, the apparent activation energy, and the Avrami parameter for crystallization are estimated on the basis of different scanning calorimetry (DSC). The sizes of grown nanocrystals in the glass matrix appear to be 30-36.5 nm and it is studied as a function of the nucleation temperature, also the peak intensity of the nanocrystalline is studied as a function of the nucleation temperature from the X-ray diffraction (XRD) measurement. The microhardness measurement shows that the Vickers microhardness (Hv) values of the heat-treated glass samples are larger than that of the based glass about 17.26%-42.04%.