We developed a light-sheet illumination microscope that can perform fast 3D imaging of transparent biological samples. The light-sheet is created by raster scanning of a Bessel Beam with one galvo-mirror. Fluorescence excited from the thin layer of the sample is de-scanned by the same galvo-mirror, and then spatially filtered by a slit so that out-of-focus fluorescence generated by the side lobes of the Bessel beam is rejected. The spatially filtered fluorescence is returned by a series of optics and is re-scanned by the same galvo-mirror across the chip of a camera such that the fluorescence image is constructed in real-time. Compared to two-photon Bessel beam excitation or other confocal line scanning approaches, our method is of lower cost, simpler, and doesn’t require calibration and synchronization of multiple galvo mirrors. We demonstrated the capability of fast 3D imaging and background rejection capabilities of this microscope with fluorescent beads embedded in PDMS.