Abstract: High accuracy spectral tunable calibration light source is a novel calibration light source, which especially accounts for the stringent calibration requirements of hyper-spectral remote sensors. A broadband and large aperture apochromatic collimator was designed. The lens worked in band of 400~1 000 nm, half field of view was 2.2, relative aperture F was 2.8, and focal length was 135 mm. According to the corrected formula of parial dispersion (P) and Abbe number (), the original optical structure was acquired, based on the principles of apochromatic lens design. The secondary spectrum was corrected well with the help of Zemax software. At last, the lens was apochromatic in the whole working band with secondary spectrum residual of about 0.04 mm, and other aberrations are balanced well. The Lens's MTFs are better than 0.8 at spatial frequency of 37 lp/mm, which meet the requirements of the light source system.