We present an analysis of grating imaging by the method of backwardilluminating modulation which is applied to study the backward diffracting interference ofgrating system. In a simple manner, the interrelation between Talbot effect and Laueffect is revealed successfully. And another achromatic effect of double grating systemwith self-achromatic-compensation by white-light illumination in Fresnel region isrepresented, Based on it, for the first time, the white-light grating imaging effect is obtained by the method of backward illuminating modulation.