Future spacecrafts have characteristics of high mobility, load diversity and so on. The platform network system of spacecraft carries most of the data exchange tasks. With the diversity demands of system complexity and task load, it is necessary to carry out reasonable network planning. In order to meet the scheduling requirements and system stability, we analyze the multi-task information flow model of spacecraft and design the strategy of network bandwidth scheduling based on time window partition. At last, the software Matlab is used to simulate the scheduling strategy. The simulation results show that this scheduling strategy can meet the scheduling requirements and system stability.