Compared with traditional optical imaging techniques, ghost imaging has the advantages of high resolution and strong anti-noise capability. While compared with single-wavelength ghost imaging, multi-wavelength ghost imaging can not only reconstruct the spatial information of the target object to be measured, but also reconstruct its color information. Firstly, the theoretical basis of multi-wavelength ghost imaging is briefly introduced. Then the color reconstruction of the multi-wavelength ghost imaging is carried out by using Hadamard illumination pattern with the multi-wavelength ghost imaging with white illumination as the experimental architecture. The optimization experiment of expanding the spectral range is proposed, that is, increasing types of the wavelength, which improves the color brightness of the reconstructed image experimentally. It is believed that the research is helpful for the practical applications of multi-wavelength ghost imaging in the field of spectrum imaging.