To detect the concentration of greenhouse gas in the atmosphere of the earth, four kinds of gas detection optical systems with the spatial resolution of 2 km, the ground swath of 500 km and the orbit altitude of 690 km are designed. The central wavelengths of the four wavebands are 1.606 μm (weak CO2), 1.660 μm (CH4), 2.064 μm (strong CO2) and 0.765 μm (O2) respectively. Their spectral resolutions are 0.08 nm/20000, 0.08 nm/20000, 0.1032 nm/20000 and 0.045 nm/17000 respectively. The whole system consists of an immersed plane diffraction grating, a Littrow optical structure and a front optical system. Its Modulation Transfer Function (MTF) at the Nyquist frequency is close to 80% and the diffraction energy in a single pixel size is close to 90%. So, the system can be used to implement hyper spectral detection.