Fourier ptychographic microscopy is a promising imaging technique which can circumvent the spaceâbandwidth product of the system and achieve a reconstruction result with wide fieldâofâview (FOV), highâresolution and quantitative phase information. However, traditional iterativeâbased methods typically require multiple times to get convergence, and due to the wave vector deviation in different areas, the millimeterâlevel fullâFOV cannot be well reconstructed once and typically required to be separated into several portions with sufficient overlaps and reconstructed separately, which makes traditional methods suffer from long reconstruction time for a largeâFOV (of the order of minutes) and limits the application in realâtime largeâFOV monitoring of live sample in vitro. Here we propose a novel deepâlearning based method called DFNN which can be used in place of traditional iterativeâbased methods to increase the quality of single largeâFOV reconstruction and reducing the processing time from 167.5 to 0.1125âsecond. In addition, we demonstrate that by training based on the simulation dataset with highâentropy property (Opt. Express 28, 24â152 [2020]), DFNN could has fine generalizability and little dependence on the morphological features of samples. The superior robustness of DFNN against noise is also demonstrated in both simulation and experiment. Furthermore, our model shows more robustness against the wave vector deviation. Therefore, we could achieve better results at the edge areas of a single largeâFOV reconstruction. Our method demonstrates a promising way to perform realâtime single largeâFOV reconstructions and provides further possibilities for realâtime largeâFOV monitoring of live samples with subâcellular resolution.