Comparing with traditional transmission imaging lens, the Offner refractive imaging lens has the advantages of wide band, small aberration, relatively large numerical aperture, compact structure and better space adaptability. In combination with the characteristics and requirements of spatial heterodyne spectroscopy (SHS), the Offner imaging lens and the light path structure are designed. Several pieces of lens are added to the exit light in order to change the pantograph ratio, while the aberration caused by the lens is eliminated by using off-axis assembly, so the requirement of variability in the magnification of interferometric fringe on localization plane on the SHS can be satisfied. Under the precondition of SHS requirements of a 0.042 numerical aperture and a -0.86221 magnification, the design example is provided, and the biggest root mean square radius of spot diagram is smaller than 1.81 μm. Finally, the imaging quality of the system is evaluated and the tolerance is analyzed, the result shows that the imaging quality can meet the imaging lens requirements of SHS, the Offner imaging of SHS can be achieved in engineering under the level of conventional machining and assembly.