In order to extend the field of view (FOV) of the light sheet microscopy system, wavefront phase modulation and digital image tiling are proposed. The intensity distribution of the light sheet at the focal plane of the objective lens after wavefront phase modulation is numerically simulated. A light sheet microscopy system is built to carry out the imaging experiments for fluorescent particles and flower pollen. The light sheet illuminates different sample positions by beam defocusing to obtain different images, which are tiled to get the FOV-extended image. FOV is extended to 3 times (about 31.93 μm) of the original field with wavelength of 488 nm and numerical aperture of 0.3 while the thickness of light sheet retains 0.81 μm. The experiment and simulation results suggest that FOV of the system can be extended by wavefront phase modulation and digital image tiling with tomographic ability not sacrificed.