The potential energy sequences of characteristic atoms were separated out by nine potential energy E-functions on the basis of larger experimental heats of formation of the L10-AuCu and L12-AuCu3 compounds only.According to these potential energy sequences of characteristic atoms,the potential energies and heats of formation of disordered Au1-xCux alloys were calculated by corresponding E-functions at 0 K;and the potential energies,heats of formation and critical Tc-temperatures of the order-disorder transitions of L10-AuCu,L12-Au3Cu and L12-AuCu3 compounds,Au3Cu-,AuCu-and AuCu3-type ordered alloys with maximal ordering degrees were also calculated at 0 K.The results obtained by both the first and present parts of this investigation were compared.Comparing the results obtained by nine E-functions,the 5th E(x,0,σ)function may be chosen for describing thermodynamic properties of the compounds,ordered and disordered phases and for establishing the phase diagram of the Au-Cu system in the future. The potential energy sequences of characteristic atoms were separated out by nine potential energy E-functions on the basis of larger experimental heats of formation of the L10-AuCu and L12-AuCu3 compounds only. According to these potential energy sequences of characteristic atoms, the potential energies and heats of formation of disordered Au1-xCux alloys were calculated by corresponding E-functions at 0 K; and the potential energies, heats of formation and critical Tc-temperatures of the order-disorder transitions of L10-AuCu, L12-Au3Cu and L12-AuCu3 compounds, Au3Cu-, AuCu-and AuCu3-type ordered alloys with maximal ordering degrees were also calculated at 0 K. The results obtained by both the first and present parts of this investigation were compared. Comparing the results obtained by nine E -functions, the 5th E (x, 0, σ) function may be chosen for describing thermodynamic properties of the compounds, ordered and disordered phases and for establishing the phase diagram of the Au-Cu system in the future.