Let S = k[x 1 , x 2 , . . . , x n ] be a polynomial ring. Let I be a StanleyReisner ideal in S of a pure simplicial complex of dimension one. In this paper, we study the Buchsbaum property of S/I r for any integer r > 0. Our first purpose is giving a characterization of Ext-modules Ext p S (S/m t , S/ J ) for any monomial ideal J , where m t = (x t 1 , x t 2 , . . . , x t n ), in terms of certain simplicial complexes. Then we consider the Buchsbaum property of S/I r . The main tool to check the Buchsbaumness is the surjectivity criterion. We see the behavior of the canonical map from Ext p S (S/m t , S/I r ) to H p m (S/I r ) from the view point of reduced cohomology groups of simplicial complexes.