The design theory of large aperture and wide spectrum refracting collimator was introduced. The refracting collimator system of the suitable glass materials, original configuration selection, and power allocation was discussed with the wavelength range of 400～1100 nm, the focal length of 2000 mm and the relative aperture of 0.1. Based on the modified relative partial dispersion P and Abbe number V, the apochromatic equations was calculated to solve the initial structure, and then the final design was optimized in the whole spectral range by Zemax software. Finally, results show that the spot diagram is better than 5 μm within the center field of view, central wavelength of wavefront aberration is better than 1/60λ and the maximum focal shift range is less than 0.33 mm, and the remaining aberrations are well revised in the design index.