In this paper, we study the solvability of nonlocal problems for second order three-point nonlinear （p,q)-difference equations. Firstly, the Green function of the boundary value problem of （p,q)-difference equation is given, and the existence and uniqueness of the solution of the problem are obtained by using the Banach contraction mapping principle and the Krasnosel"skii fixed point theorem on the cone. Secondly, Lyapunov inequality for nonlocal problems of linear （p,q)-difference equations is given. Finally, application examples are given to verify the correctness of the results.