According to the third order aberration theory of binary optical element, the optical coupler system with one diffractive surface, telecentric optical path structure in the object space is shown with calculation and optimization of optical design software ZEMAX, whose operating wavelength is 0.4～0.7 μm, focal length is 27 mm, and optical length is 62.9 mm. The result is available for the image fiber bundle, whose single core diameter is 16 μm and section diameter is 6 mm. Compared with the conventional optical coupler, the hybrid refractive-diffractive system offers considerable reduction in the apparent size, weight, and improves the image quality. The simulation results of optical design software are proved well by the experiments on scenic imaging both indoors and outdoors.