Ba0.6Sr0.4TiO3 ceramic was synthesized by the sol-gel method combined with the solid-state reaction. Phase composition and microstructure analyses indicate that pure BST phase with aggregated nanograins can be achieved. The dielectric properties change with sintering temperature, and reach the maximum at suitable temperatures. The highest dielectric constant of 4351 is obtained at 100 Hz for 1275 ℃sintered sample that is 2 times greater than that of the original sample, which indicates the dielectric properties can be modulated by grain size and density. The results show that Ba0.6Sr0.4TiO3 is a promising candidate for microwave applications.