Abstract: The electronic structure , density of states and charge populations of the Mg doped CaMnO 3 oxide for Ca site has been studied by the psudo-potential density funtional theory calculation method , the electrical properties of the doped oxide have been analyzed thereafter .The calculational results show that the Mg doped CaMnO3 oxide has indirect band gap yet , the band gap has been slightly decreased from 0. 756 eV to 0.734 eV.The peak value of density of states curves locates at -0.8 eV for the pure CaMnO3 oxide and the Mg doped CaMnO 3 oxide .The Mn contributes less to density of states at Fermi level , however the O atom and the Ca atom contribute more to density of states at Fermi level .The Mg has stronger capability of releasing electrons into the system than that of the Ca , it should belong to electron carrier doping type for the Mg doping for Ca for the CaMnO 3 oxide system .The Mg doping for Ca should enhance the electrical conduction capablity for the CaMnO 3 oxide , the electrical property should be strengthed .

Key words: The electronic structure , density of states and charge populations of the Mg doped CaMnO 3 oxide for Ca site has been studied by the psudo-potential density funtional theory calculation method , the electrical properties of the doped oxide have been analyzed thereafter .The calculational results show that the Mg doped CaMnO3 oxide has indirect band gap yet , the band gap has been slightly decreased from 0. 756 eV to 0.734 eV.The peak value of density of states curves locates at -0.8 eV for the pure CaMnO3 oxide and the Mg doped CaMnO 3 oxide .The Mn contributes less to density of states at Fermi level , however the O atom and the Ca atom contribute more to density of states at Fermi level .The Mg has stronger capability of releasing electrons into the system than that of the Ca , it should belong to electron carrier doping type for the Mg doping for Ca for the CaMnO 3 oxide system .The Mg doping for Ca should enhance the electrical conduction capablity for the CaMnO 3 oxide , the electrical property should be strengthed .