The discrete variational (DV)-Xα cluster model is used to study the surface structure of Ge film which developed on Si (001) substrate using Te as a surfactant. The X-ray photoelectron spectra were calculated and compared with experimental data. From the comparison, it is found that Te dimers adsorb on the hollow site of Ge (001) -2×1 surface and their bonding direction is perpendicular to that of Ge dimers. The results suggest that the Te dimers terminate the dangling bonds of Ge film surface and exchange their site with evaporated Ge atoms at the adsorption site.