In order to fulfill the observations of near Infrared (IR) CO2 absorption bands in reflected sunlight, a kind of high spectral resolution near infrared CO2absorption bands imaging spectrometer was designed based on the principle of imaging spectrometer and the theory of optical design. A simple planar reflection grating spectrometer approach consisting of an entrance slit, a two-element collimator, a planar reflection grating and a two-element camera lens was presented. Common glasses were chosen and aspheric elements with simple conics were allowed with a view to minimizing the number of optical surfaces. The optical system of the spectrometer was optimized by using ZEMAXoptical design software. The analyzed results show that the spectrometer’s spectral range is 1591-1621nm, resolution is <0.08nm, F-number is 1.8, and these all satisfy the requirements.