Abstract: Models for multiphase flow in embedded fractures and multi-fracture-intersecting networks were built to accurately characterize the flow of multiphase fluid in complex fractures in shale oil reservoirs. The numerical simulation method was utilized to analyze the flow law of multiphase fluids in the multi-fracture-intersecting networks. The results show that the numerical simulation method for the multiphase flow in the fracture networks solves problems such as single fluid type characterization, large fracture scales, high requirements for meshing accuracy, and discontinuity of fluid parameters at the fracture interface. This method can be used to assess the communication scale of hydraulic and natural fracturesand the distance between them. The formation pressure calculated by the numerical simulation method can be used to characterize the pressure variation near the fracture networks of shale oil reservoirs with the production time. The numerical simulation method proposed in this paper shows high efficiency in computing, and provides a new technical approach for the evaluation of shale oil reservoirs.