The ground-state properties of Nb(C1-x□x) have been calculated by using a LDF-LM-TO-ASA supercell method. The calculation was performed by quadruple unit-cell such as Nb4C3□0, Nb4C3□1, Nb4C2□2 ,Nb4C1□3 and Nb4C0□4. The equilibrium lattice constant a(x) , bulkmoduli B(x), Debye temperatures θD(x) and heat of formation h (x) obtained from LM-TO calculation were combined with Bernoull's distribution. These results are in agreement with experimental data.