The idea of propagation-invariant Complementary Beam (CB) to Bessel beam was proposed. Based on the Huygens-Fresnel principle and the superposition of coherent light field, the general form of CB′s spectrum is suggested. The phase distribution of complex amplitude spectrum is optimized with the aid of genetic algorithm, in doing so the scanning complementary beam light-sheet enables to approximate the side lobes of Bessel light-sheet to the utmost. Thus, the substraction of two scans can eliminate the influence of the side lobes to produce a large FOV, homogeneous and thin light-sheet. The employment of the complementary beam into light-sheet fluorescence microscopy is a promising method to reduce the background signal as well as enhance the imaging quality.