Abstract: Under given illumination and observation conditions, in order to reconstruct the spectral reflectance of the object surface from the camera response signal to achieve high-precision color reproduction, multi-spectral imaging technology was used to acquire multi-spectral image response of an object.The principal component analysis, matrix R and the new regularization matrix R method were used to analyze the theoretical analysis of spectral reflectance reconstruction.The results of the research were verified experimentally in the color reproduction of mural color blocks.The reconstructed spectral reflectance and color reproduction data of mural color blocks were obtained.At the same time, the color reproduction results of mural color blocks based on regularization matrix R method were evaluated.The results show that the regularization matrix R method is superior to the principal component analysis and matrix R method in the spectral accuracy and reconstructed accuracy.Compared with the principal component analysis and the matrix R method, the color difference is reduced by 0.0732, the fitness coefficient is increased by 1.10%, the root mean square error is reduced by 0.0035, and the spectral matching partial index is reduced by 0.0225.This method can meet the needs of high-precision color reproduction, which is suitable for digital archiving of cultural relic artwork, restoration of cultural relics and other fields.