In the design process of civil aircraft avionics data network, bandwidth resources is allocated reasonably to meet the data transmission requirements of network member systems. Due to the nonuniformity of network bandwidth requirements distribution and other factors, there may be local bandwidth resources insufficiency in the design process, so it is necessary to carry out a local optimization design based on the preliminary bandwidth resource allocation results is necessary. This paper proposes a method to reduce the utilization rate of link bandwidth resources between switches by identifying the link and end system with the highest utilization rate of network bandwidth resources, and adjusting the connection relationship of physical links. Taking a typical ARINC664 network as an example, the reduction of singleround optimization is over 15%. On the one hand, the optimization design method of network bandwidth resource allocation can effectively solve the problem of insufficient local bandwidth of aircraft network, reduce the risk of network congestion, queuing and packet loss, and ensure the network certainty; On the other hand, the current distribution results can keep the current allocation results as much as possible and minimize the impact of design optimization changes on network delay performance and network routing.