SrLnAlO4 (Ln Nd and Sm) ceramics with K2NiF4 structure were prepared by a solid state reaction approach, and their microwave dielectric characteristics were evaluated together with the microstructures. The single phase dense SrNdAlO4 and SrSmAlO4 ceramics were obtained by sintering at 1450-1475℃ and 1475-1500℃, respectively, and the good microwave dielectric characteristics were achieved: (1) ε = 17.8, Q · f = 25,700GHz, τ f = −9ppm/℃ for SrNdAlO4; and (2) ε = 18.8, Q · f = 54,880GHz, τ f = 2ppm/℃ for SrSmAlO4 dense ceramics. The Q f value significantly increased with increasing sintering temperature.