A simple and sensitive method for the speciation, separation and preconcentration of Cr(VI) and Cr(III) in environmental water was developed. The procedure presented based on two forms of chromium show different adsorption capacities on the silica gel G loaded nano-barium strontium titanate(GBST) at different pH values, that is, Cr (III) selectively retained at pH 7–14, but Cr(VI) can’t be adsorbed. Whereas Cr (VI) retained at pH 1, but Cr(III) can’t be adsorbed. Hence complete separation of the two forms of chromium is possible. Retained Cr(III) and Cr(VI) were eluted with 1 mol•L −1 HCl and 1 mol•L −1 NaOH, respectively. The Cr(III) and Cr(VI) concentration was measured by atomic absorption spectroscopy. The method was successfully applied for the speciation of chromium in environmental water samples with successfully results.