Abstract: Relativistic Hartree Fock (RHF)theory is adopted to describe properties of exotic nuclei near drip line. In order to investigate the contribution of Fock term and isovector mesons to the properties of exotic nuclei and to avoid effective interaction which is not unique, the density dependent relativistic Hartree (RDH) and relativistic Hartree Fock (RDHF)theories without free parameter are extended to describe the properties of exotic nuclei. The properties of calcium isotope chain are calculated in the RDH and RDHF approaches, particularly, the contribution of the Fock term and isovector mesons to the properties are investigated. It turns out that the influence of the Fock term and isovector mesons on the properties of neutron very rich nuclei, such as binding energies, RMS of neutron radius, distribution of neutron density, is very different from those of stable nuclei. The importance of study on the properties of nuclei near drip line and theoretical model used in this paper are briefly discussed.