The spinel was calcined at temperatures in the range of $1000^{circ}C$ to $1300^{circ}C$ with $100^{circ}C$ interval to evaluate the effect of calcination temperature on mechanical properties of spinel-glass dental composites. Although the average particle size of spinel calcined at temperatures from $1000^{circ}C$ to $1200^{circ}C$ was within 2.8~3.0 $mu extrm{m}$, the spinel calcined at $1300^{circ}C$ was 4.66 $mu extrm{m}$ due to abnormal grain growth. Shrinkage and pore size of the spinel preform decreased and increased, respectively, as calcination temperature increased, indicating that the calcination temperature was significant to the powder compaction and the densification of the composites as a result of particle size and distribution. The optimum strength and the fracture toughness of the composite calcined at $1200^{circ}C$ were 284$pm$40 MPa, 2.5$pm$0.1 MPaㆍ$m^{1/2}$ respectively. Optical experimental results showed that transmittance of the spinel-glass composite in the visible region was twice higher than that of the alumina-glass composite, suggesting that the spinel-glass composites possessed better aesthetic properties for all-ceramic dental crown application.