Thin films of SrCuO2 with tetragonal structure have been epitaxially grown on SrTiO3 (001) substrates by high-oxygen pressure sputtering technique. The interface structure between SrCuO2 and SrTiO3 and configuration of defects in SrCuO2 thin films have been characterized by means of high-resolution transmission electron microscopy. Two types of film-substrate interface structure coexist and are determined as bulk-SrO-TiO2-Sr(O) -CuO2-Sr-bulk and bulk-SrO-TiO2-SrO-Sr(O) -CuO2-Sr-bulk. The planar faults with double SrO atomic layers in (100) planes in SrCuO2 thin films are observed, which mainly arise from the coalescence of these two types of film-substrate interface structure. Meanwhile, planar faults in (110) planes are observed in thin films and structural models are proposed. (C) 2010 Elsevier B.V. All rights reserved.