Using the multiple scattering cluster method (MSC), we have calculated the oxygen K-edge NEXAFS spectra of formate molecule which is the intermediate in the catalytic decomposition of formic acid over Cu(110) surface. The calculation shows that the formate is adsorbed at the short-bridge site of Cu(110) surface, the bond-lengths LC-0 and LCu-o are 1.26±0.01? and 1.975±0.02? respectively, the O-C-O bond angle is in the range of 130°-134°. This result agrees with that of photoelectron diffraction, and demonstrates that the multiple scattering cluster method is an effective one for the surface structure determination.