In this paper, we report the successful preparation of barium strontium titanate (BST) microcubes with an average size of 1 mu m via the composite-hydroxides-mediated approach. X-ray diffraction (XRD), scanning electronic microscopy, and transmission electronic microscopy technologies are used to characterize the structure and morphology of the samples. Energy-dispersive spectrometer is used to evaluate the composition and phase segregation of the samples. The ultraviolet to visible absorption spectrometer is applied to evaluate the optical properties of the BST powders. The results indicated that the difference in the ion radii of Sr4+ and Ba4+ leads to the moderate phase segregation in the BST powders. Rietveld refinement of the XRD patterns obtained clearly shows the coexistence of distinctive phases and the volume fractions of Sr-rich phases increase by increasing the content of strontium. The powders are found to show cubic-shaped microparticles with the exposed {100} facets. Optical absorption edge (E(g)) of the BST samples indicates an obvious relationship with the barium contents, which is attributed to the structural segregation in the samples.