Optical sectioning fluorescence microscopy provides high contrast images of volumetric samples and has been widely used for many biological applications. However, simultaneously acquiring multi-color fluorescence images require additional optical elements and devices, which are bulky, wavelength specific, and not cost-effective. In this paper, wavelength-coded volume holographic gratings (WC-VHGs) based optical sectioning fluorescence microscopy is proposed to simultaneously offer multi-color fluorescence images with fine out-of-focus background rejection. Due to wavelength degeneracy, multiplexed WC-VHGs are capable of acquiring multi-wavelength fluorescence images in a single shot, and displaying the laterally separated multi-wavelength images onto CCD. In our system optical sectioning capability is achieved through speckle illumination and HiLo imaging method. To demonstrate imaging characteristics of our system, dual-wavelength fluorescence images of both standard fluorescent microspheres and ex vivo mT/mG mice cardiac tissue are presented. Current results may find important applications in hyperspectral imaging for biomedical research.