Suppose that Q is a family of seminorms on a locally convex space E which determines the topology of . In this paper, first we define the notation of the duality mappings in locally convex spaces. Then we introduce an implicit method for finding an element of the set of fixed points of a Q-nonexpansive mapping. Then we prove the convergence of the proposed implicit scheme to a fixed point of the Q-nonexpansive mapping in Tau_Q.