The interaction energies of solute atoms with edge dislocation pairs in Cu-Ni-Sn solid solutions were calculated by first principles.The results show that the dislocation has a strong force on Sn atom and it is increased with the increase of Ni content in the matrix.The maximum energy difference of dislocations acting on a single Sn atom is about 89.83 kJ/mol at different positions in pure copper matrix

and that on single Sn atom at different positions in（Cu

Ni）matrix containing 20% Ni is about 128.25 kJ/mol.The preferred distribution of Sn atoms is at the Gposition just below the front edge dislocations

and the Sn atoms far away from the dislocations converges around the Gposition under the action of energy difference.Dislocation in solid solution has a weak interaction energy to Ni atom（the maximum energy difference about 18.87 kJ/mol）

and the preferential distribution of Ni atom under dislocation is not obvious.