Non-relativistic and relativistic band structures of NaCl type uranium compounds were calculated with tight-binding approximation based on the rigid band concept. The calculations revealed that the narrow 5f band played important role, and from the desity of states curve the Fermi levels of these compounds were found to lie on or near the 5f band. Moreover, spin-orbit and crystalline field effects were seen to split the 5f band further into five sub-bands. The Fermi levels proved to be related to the lowest sub-band, in which two states were included, and the width of this sub-band was estimated to be 0.05eV. The validity of the foregoing band structure based on calculation is discussed in reference to specific heat at low temperatures and also to magnetic properties.