BaTiO3 nano-particles with a size range of 20-70 nm were synthesized at 70 degrees C through a simple wet-chemical reactions between barium hydroxide octahydrate (Ba(OH)2 x 8H2O) and meta titanic acid (H2TiO3) in ethanol/water mixed solvent systems. It was found that the volume ratio of ethanol to deionized water is a key controlling parameter to determine the phase formation and particle size of BaTiO3. Single-phase cubic perovskite BaTiO3 started to be formed in solution containing above 40 volume percent of ethanol. From the field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) analysis, the as-prepared BaTiO3 exhibited the aggregated morphologies. The surface properties were characterized by the nitrogen adsorption isotherms curves. The effects of these aggregates on the electrical performance in BaTiO3/epoxy nano-composites were also examined.