The barium-strontium titanyl oxalate (BSTO) precursor powder was prepared successfully by using the simple oxalate chemical coprecipitation method.The pyrolysis of BSTO at 905℃ in air produced barium-strontium titanate (BST) powder.BST powder was characterized with SEM

TEM，XRD and FT-IR

which revealed that the powder was spherical

highly pure

perovskite

and the average particle diameter was 36 nm.The adsorption behavior of nanometer-sized BST powder for cadmium ion in water was investigated with FAAS.It was found that the powder had adsorption capacity towards cadmium ion and the amount of adsorption was closely related to the pH of water.The adsorption dynamics followed the rate equation of Langmuir and Bangham.The adsorption isotherm accorded with Langmuir and Freundlich equation.The adsorption was characterized by physisorption with spontaneous heat release.