Mechano-chemical modification (MCM) of nanodiamond was conducted with a stirring mill. A new type of silane coupling agent, GW was chosen as its modifier. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) were employed to study the surface properties of nanodiamond before and after treatments. Results showed that the peaks related to GW and the ball (for example, Fe, Si and Cl) appeared obviously after its MCM on their XPS spectra and mostly disappeared after its further purification with acid X or Y. A new peak located at 1382.48cm-1 was very strong after further purification. It was proven by their FT-IR spectra.