Space-based atmospheric remote sensing urgently requires multi-model hyperspectral imager. Based on the research objective of multi-model space-based atmospheric remote sensing, an optical system of space-based multi-model hyperspectral imager with nadir and limb models is designed using a scanning system, an off-axis parabolic telescope and a spectral imaging system with a cascade double spectrometer. The instantaneous field of view of hyspectral imager is 1.8°×0.045°, relative-aperture is 1/2, and working waveband is from 250 nm to 500 nm. The waveband from 250 nm to 500 nm is devided two wavebands, one is from 250 nm to 330 nm, the other one is from 320 nm to 500 nm. Ray tracing, optimization are performed by ZEMAX-EE software. The root mean square (RMS) spot radius for different wavelengths are less than 9.5 μm. The spectral resolution is 0.17 nm in the waveband from 250 nm to 330 nm, the spectral resolution is 0.37 nm with waveband from 320 nm to 500 nm, and both of them satisfy the requirement of specification which is less than or equal to 0.6 nm. The modulation transfer function (MTF) for different wavelengths of hyperspectral imager is more than 0.9 at characteristic frequency in the spatial direction. The design results satisfy the requirements of imaging quality, and is suitable for the application of space-based remote sensing.