We have developed a new potential function for classical molecular dynamics (MD) calculations of III-V compound semiconductors. The key idea for the new potential function is incorporation of the ionic nature of the bonds into the conventional Tersoff potential. It has been found that this potential can be used for the simulation of the MBE epitaxial growth for the III-V compound semiconductors, Using this potential we have compared the initial growth stages of GaAs, AlAs, and InAs on GaAs substrates and found that the lattice mismatch causes serious distortion in the arrangement of the atoms even for the first layer.