The BiFeO3-CoFe2O4 nanostructures with volume fractions of 65:35, 1:1, and 33:67 grown on SrTiO3 substrates were investigated. The dependence of BiFeO3-CoFe2O 4 nanostructures on the substrate orientations is attributed to the different growth modes of the two phases. The ferroelectric and magnetic properties and the degree of the coupling are critically dependent on the morphology of the nanostructures which include domain patterns, shapes, and the interfaces. The possible configuration of the crystalline nucleus on the substrate is a Wulff shape that has been cut off by the substrate, translated by the signed distance from the origin. It has been reported that the BiFeO 3-CoFe2O4 nanostructures are ideal for future study on the morphological dependence of magnetoelectric coupling.