A method for reconstructing color images has steps of using a spectrum-acquiring device to acquire spectral data of a plurality of sample color blocks and calculating coefficients of a basis matrix of the sample color blocks; obtaining digital counts of the plurality of sample color blocks with a digital camera; obtaining a conversion matrix in accordance with the coefficients of the basis matrix and the digital counts; acquiring digital counts of an original image with the digital camera, and generating a reconstructed image in accordance with the digital counts of the original image and the conversion matrix; and varying the conversion matrix in accordance with a new light source, and computing to generate a reconstructed image corresponding to the new light source in accordance with the digital counts of the original image and the varied conversion matrix.