Abstract: A large plane array, high resolution and small volume multi-spectral imaging optical system was designed based on the application of the liquid crystal tunable filter (LCTF). The LCTF has advantage of high spatial resolution, high spectral resolution, flexible wavelength and short tuning time. Using LCTF, a multi-spectral image whose size was about 210 mm148 mm with resolution of 350 ppi could be realized. The spectral range of this multi-spectral imaging system was from 420 nm to 720 nm and the spectral resolution of which was 10nm. The results show that when the spatial resolution is 91lp/mm, the on-axis 0 field and off-axis 1.0 field MTF at 31 wavebands are not less than 0.30, and the distortion of TFOV is less than 0.1%. Therefore, this system has good imaging quality and can be used to acquire and analyze the large plane array and high resolution spectral image.