In this paper a model of compressed atom for condensed matter is described. The atom is supposed to be enclosed in a sphere of radius R₀, which is determined by the matter density. The orbital energies and the wave functions are obtained from the solutions of the Dirac equation in a self-consistent field with different boundary conditions. We find when the matter densities are small, the energy levels are just like the situation of free atom, when the matter densities are large, The energy levels are changed greatly. As an example the calculated results of compressed Iron are presented.