Mass-transfer coefficient for anion exchange was determined for commercially available strong-base anion exchange resin of Cl^- type in use to remove nitrate in water. Experiments were performed over an initial solution concentration range from 5 to 50ppm nitrate and temperature range from 283 to 323K in 2L batch reactor. Effective diffusion coefficient was obtained in the range from 9.67×10⁸ to 1.67×10⁶ cm²/sec for initial concentration change, and from 6.09×10^-7 to 3.98×10^-6 cm²/sec for reaction temperature change. Activation energy during the diffusion was calculated as 36 kcal/mol.