The first nearest neighbor interatomic potentials of Ni0.75AlxV0.25-x alloy’s for L10, L12 and DO22 phases were calculated out according to the formula which were referenced on the relation equation between interatomic potentials and long range order parameters by Khachaturyan. Then we simulated the precipitation process and the final morphology of Ni0.75AlxV0.25-x alloy using the calculated potentials based on the Microscopic Phase-field method. The results show that the interatomic potentials of L10, L12 and DO22 phases will increase while the temperatures or the atom’s concentration rise. And the interatomic potentials, which change with the temperature and the concentration, match well with the earlier values. The simulation results can obtain the pre-precipitation phase L10, the stable phase L12 and the second phase DO22. And the alloy precipitation morphology is found to be in agreement with the experimental result. The inversion of interatomic potentials by phase field method expands the application of the phase field method in the alloy design.