The properties of Sb adsorption on the Si(001) substrate have been studied by us ing the semiempirical approach for calculating the surface stress based on the C hadi's model and the Green's function method. It is shown that the Sb atoms form symmetric dimers on the Si(001) surface with the dimer bond length being 0.293n m. No significant relaxations can be found in subsurface layers. The Sb/Si(001)2 ×1 surface is shown to be under tensile stress of 1.0eV/(1×1cell) along the di mer direction and compress stress of-1.1eV(1×1cell) perpendicular to the dimer direction. The main contribution of surface stress of Sb/Si(001) comes from the top three layers.