We consider the existence of solutions for a class of nonlinear high order q-symmetric difference equations.The solution of BVP is acquired by calculating.We construct a Banach space and get the uniqueness of solution by making use of Banach space completely continuous operator's fixed theorem,and the existence of the solutions is obtained by using the Schaefer's fixed point theorem.The proofs of these results is based on Banach space completely continuous operator's fixed theorem and Schaefer's fixed point...