The microwave dielectric properties of (I-x)CaTiO$_{3}$-xLaAIO$_{3}$ were investigated. The solid solution of (1-x)CaTiO$_{3}$-xLaAIO$_{3}$ had the perovskite structure in the range of all compositions. The crystal system of (1-x)CaTiO$_{3}$-xLaAIO$_{3}$ was transformed to orthorhombic(x.leq.0.4), psudo-cubic(x=0.5), and rhombohedral (x.geq.0.7) in turn, as the amount of LaAIO$_{3}$ increased. The dielectric constant and temperature coefficient of resonant frequency of solid solution were decreased with the content of LaAIO$_{3}$, whereas, the value of Q . f$_{o}$ was increased. The microwave dielectric material having Q . f$_{o}$ = 32, 500, .epsilon.$_{r}$ = 42, and .tau.$_{f}$ = 5 ppm/.deg. C was obtained from the 0.35CaTiO$_{3}$-0.65LaAIO$_{3}$ composition sintered at 1600.deg. C for 4hrs.hrs.hrs.