During the past decades, the structured illumination microscopy (SIM) has been drawing great attention for both the technique development and applications. However, the conventional SIM that uses a spatial light modulator for fringe projection often has limited imaging field of view. Therefore, we propose a large-field SIM method that combines a 2D grating for fringe pattern projection and an SLM for selecting fringe orientation and performing phase shifting digitally. The proposed SIM technique breaks the bottleneck of fringe number limited by the digital projection devices, while maintaining the advantage of high-speed (digital) phase shifting of conventional SIM. An algorithm of spatial reconstruction is developed to improve the super-resolution imaging speed. Finally, a SIM fluorescence microscopy system is developed. A large field view of 1 380 μm × 1 035 μm with a 20 × / NA 0. 75 objective is experimentally demonstrated, and an enhancement of 1. 8 times higher resolution is realized. The spatial reconstruction algorithm can greatly reduce the computational time of super-resolution reconstruction.