Adsorption of phosphate from aqueous solution has been conducted using calcined scallop shells (CSS), and XRD spectra, TG/DTA signals and pore properties (BET) of CSS were characterized. The influences of calcination temperature of scallop shells, pH, adsorption time and concentration on the phosphate adsorption using CSS were studied in batch adsorption experiment. The XRD spectra showed that CaO appeared after calcination at 800°C, the TG/DTA result exhibited decreasing weight around 38% from 600 to 800°C and BET surface area portrayed increasing value after calcination process at 800°C. The solution pH on the phosphate adsorption had no significant effect by calcination at 800°C (CSS-800). A comparison of kinetic models applied to the adsorption data by CSS-800 was evaluated with pseudo-first order and pseudo-second order model, and the experimental data were fitted well to pseudo-second order kinetic model, while the result of isotherm studies had an approach to Langmuir method with linear regression of 0.998. The adsorption amount of CSS-800 was 30 times higher than scallop shell without calcination.