L10-disorder phase boundaries for Fe-Pd system are calculated by combining first-principles FLAPW electronic structure calculation with Cluster Variation Method. The total energy calculation at the ground state well predicted the global tendencies of the phase diagram. The calculated transition temperature of L10-disorder based on the free energy formulated by Cluster Variation Method is in good agreement with experimental one. The incorporation of thermal vibration effects further improves the agreement. The shift of the congruent composition from the stoichiometry is, however, not realized by the present calculation.