Abstract Based on a surface/interface continuum theory, a theoretical study of predicting the effective dynamics properties of nanocomposites with elliptical nano-fibers is presented. The extended version of effective medium method and coherent interface model are introduced to simplify the composites with randomly distributed elliptical nano-fibers. The conformal mapping method is applied to solve the problem of typical elliptical nano-fiber. The effective elastic modulus of nanocomposites is obtained on the basis of the derived imperfect interface conditions. High accuracy of the method is demonstrated by comparing with the solutions of cylindrical nano-fibers. The effects of the shape of the nano-fibers, the material properties of interface, and the wave frequency on the dynamic shear modulus are analyzed. It is found that the interface effect is significantly related to the shape of elliptical nano-fibers. The interacting effects of the shape and the incident direction of stress waves are also examined.