An artificially modulated magnetic Co/Pd multilayer is one of the promising candidates for high density magneto-optic (MO) recording media, due to large Kerr rotation angle in the wavelength of a blue laser beam. however, since multilayer structure, as well as amorphous structure, is a non-equilibrium state in terms of free energy and MO recording is a kind of thermal recording which is conducted aound Curie temperature (Tc) of the recording media, when the multilayer is used for the MO recording media, changes in the multilayer structure are occurred as the amorphous structure do. Therefore, the assessment of the structural stability in the Co/Pd multilayer is crucially important both for basic research and applications. As the parameter of the structural stability in this research, modulation amplitude and particle size of the Co/Pd multilayer are measured in terms of Ar sputtering pressure and heat treatment temperature. From the results of the research, we find out that the magnetic exchange energy in the structural changes of a magnetic multilayer structure and suggest the operating temperature range for MO recording in the Co/Pd multilayer for the basic research and applications, respectively.