The optical configurations of off-axis spherical lens and off-axis correcting lens imaging spectrometer are designed. Based on the optical system of off-axis spherical lens imaging spectrometer, the spectrometer with off-axis lens is designed. This system adopts an off-axis lens in order to adjust large field aberration and avoids large diameter concentric lens. One prism corrects nonlinear dispersion and meets the request of spectral resolution. Distortion is controlled through adjusting off-axis angle and mirrors′ focus, which compensate spectral curve and decrease residual aberration. It is easy to reduce production difficulty. The characteristic of two systems is discussed from the aspects of engineering layout, production difficulty and image quality. And the result of spectral nonlinear and slit curve is shown. The minimum modulated transfer of off-axis spherical lens system is 75 percent better than the value 60 percent of off-axis correcting lens. The front system uses a silica lens which diameter is larger than 200 mm. The material uniformity and surface precision of the latter system is far better than the front system, and the production difficulty is decreased. The latter system considers the matching with mechanical structure, and it is more feasible for the distance between slit and the first mirror of latter system. The spectral resolution of front system is close to the latter, and the slit curve of the front system is slightly better than the latter system. The comparison shows that the latter is optimal optical layout, and it can be applied to remote sensing working at short wavelength.