The paper aims to develop a special light source and multi-spec imaging system to solve the color measurement problem of rainbow holographic in roll-to-roll printing. The special dome light source was designed based on the diffraction inhibition model to achieve uniform light incidence (−π/2 ~ π/2) on the irradiated surface as integrating sphere. The multi-spec CCD camera, which was similar to the traditional RGB three-channel camera, can generate 12 ~ 36 spectral channels images. The dome light source achieved uniform light intensity, had apparent inhibiting effect on diffraction light on surface of holographic printed product, and weakened the dispersion effect of diffraction grating. And spectral characteristics in multiple channels of product were obtained by multi-spec camera imaging. The multi-spec imaging system with dome light source design has good color expression, which can achieve accuracy within two degrees of color difference.