The crystallization behavior and mechanical properties of CaO-Al2O3-SiO2 (CAS) system glass-ceramics with addition of Y2O3 were investigated. The optimal sintering temperatures of all heat-treated glasses were altered and the crystallization was accelerated with Y2O3 addition,and only wollastonite as a main crystalline phase was precipitated. The volume fraction of crystalline phase and density were increased with Y2O3 addition. The results suggest that the CAS glass-ceramics would get the lowest sintering temperature and optimal microstructure with the addition of Y2O3 by 3.25 %. The bending strength has a maximum due to the oriented and interlocked wollastonite crystal,which causes crack divert or blunts to limit the further development of the flaw size and increases the surface energy of fracture.