Initial deposition processes of Mg on MgO were studied using our novel quantum chemical molecular dynamics (QCMD) simulator. This novel simulator was developed on the basis of our tight-binding quantum chemical molecular dynamics (TB-QCMD) simulator and our molecular dynamics simulator. The justification of the novel QCMD simulator was shown by the excellent agreement of the QCMD result with the first-principles results and experimental results for the physicochemical properties of the MgO crystal. Dynamic behaviors of Mg atom deposited on the MgO(001) and (111) surfaces were simulated by the novel QCMD method. It was shown that the mobility of Mg deposited on the MgO(001) surface was larger than that on the (111) surface, which suggests the difference between the interaction of the deposited Mg atom with the MgO(111) surface and that with the MgO(001) surface.