Abstract: The microstructure of CaO-P₂O₅-SiO₂-MgO-F glass-ceramics during crystallization were investigated and the crystallized phases were identified with DTA (Differential Thermal Analysis), SEM (Scanning Electron Microscope) and XRD (X-ray Diffraction) techniques. The mechanical properties such as bending strength and fracture toughness, as well as their changes with advancing crystallization were determined. The results show that the changes of the mechanical properties are correlated with the microstructures. The sample heated up to 810℃ and soaked for 4h has smaller crystalline size and less volum fraction of fluorophlogopite, so it has higher bending strength (about 190 MPa), and higher crack toughness (about 2.63 MPa·m¹²).