The invention discloses a global flow level network simulation method, system and device, and the method comprises the steps: constructing a global simulation network topology architecture to form a simulation environment, generating a simulation task through a task generator, dividing the simulation task into a plurality of stages, and storing each stage of the simulation task into a global variable for global call; the method comprises the following steps: continuously updating time information transmitted by flow objects in a global simulation network topology architecture through a global refreshing strategy, determining a flow event of which the time is shortest for each global flow object, and after the current flow object completes the flow event, calculating flow event completion time expected values of other flow objects through refreshing; global stage information is obtained through a global control strategy, whether all flow objects in a certain stage complete flow events or not is detected, so that the end of the stage of the simulation task is predicted, and a test result of the simulation task is obtained. According to the network simulation scheme provided by the invention, the resource consumption is reduced, the calculation time is shortened, and meanwhile, the simulation correctness is ensured.