We have employed density functional theory (DFT) to calculate the carbon K-edge NEXAFS spectroscopy of 4-methylbenzenethiol (4-MBT) on gold surface. Polarization-dependent NEXAFS spectra of 4-MBT at different orientation angles are systematically analyzed. The pi* resonance at 285 eV, which is the result of the transitions from 1s orbitals of carbon atoms in benzene ring to the lowest unoccupied molecular orbital (LUMO), is selected to study the orientation of 4-MBT molecule on the gold surface. In comparison with the experimental results, it is found that the benzene ring of 4-MBT is tilted by 33 with respect to the gold surface. (C) 2015 Elsevier B.V. All rights reserved.