The configuration of photosensitive dye molecules with respect to AgBr lattice is investigated by transmission electron microscopy and electron diffraction, using merocyanine dye (3-ethyl-5-2-(3-ethyl-2-3H)-benzothiazolylidene)-ethylidene]-2-thioxo-4-thiazolidinone; BTET) films vacuum-deposited on (100) and (111) AgBr surfaces. Island and oriented growth of the dye films, in α-phase (triclinic), is found on these AgBr surfaces. The observed epitaxial relations are as follows: (155) [01¯1]_BTET//(100)<011>_AgBr on the (100) AgBr surface and (011) [ 011]_BTET//(111)<101>_AgBron the (111) AgBr surface, where the BTET molecules are adsorbed in edge-standing on the AgBr surfaces. The J-absorption peak is observed in optical spectra of these BTET films, which indicates that they form J-aggregates.