Transparent ferroelectric ceramics are valuable for many applications in electro-optical devices. In this paper, transparent barium strontium titanate (BST) ceramics were prepared by spark plasma sintering and thermal treatment. The microstructures and optical properties of the transparent BST samples were investigated. The densities of the BST samples were nearly theoretical and the samples were optically transparent. Both the transmittances at 633 nm of the Ba0.3Sr0.7TiO3 and Ba0.4Sr0.6TiO3 ceramics with a thickness of 0.3 mm are over 74%. The lead-free optical transparent ferroelectric BST ceramics are promising candidates for electro-optical applications.