(Zr0.8Sn0.2)TiO4 nanopowders for microwave ceramics were prepared by a hydrothermal synthesis route. Effects of hydrothermal conditions on crystal structure, morphology and sintering performance of the powders were characterized by X-ray, SEM and TG-DTA, respectively. The powders with mean size of 80 ~ 200 nm was obtained. Ceramics with 92.3% of theoretical density were fabricated at 1260°C with the powders. Dielectric properties of the samples were measured and it gives a dielectric constant of 35-36 and Q×f value of 4500-10000 GHz.