###### Abstract  
Large-scale low Earth orbit satellite networks (LSNs) have been attracting increasing attention in recent years. These systems offer advantages such as low latency, high bandwidth communication, and all terrain coverage. However, the main challenges faced by LSNs is the calculation and maintenance of routing strategies. This is primarily due to the large scale and dynamic network topology of LSN constellations. As the number of satellites in constellations continues to rise, the feasibility of the centralized routing strategy, which calculates all shortest routes between every satellite, becomes increasingly limited by space and time constraints. This approach is also not suitable for the Walker Delta formation, which is becoming more popular for giant constellations. In order to find an effective routing strategy, this paper defines the satellite routing problem as a mixed linear integer programming problem (MILP), proposes a routing strategy based on a genetic algorithm (GA), and comprehensively considers the efficiency of source or destination ground stations to access satellite constellations. The routing strategy integrates ground station ingress and exit policies and inter-satellite packet forwarding policies and reduces the cost of routing decisions. The experimental results show that, compared with the traditional satellite routing algorithm, the proposed routing strategy has better link capacity utilization, a lower round trip communication time, and an improved traffic reception rate. LEO satellite network; routing strategy; multi-commodity flow; heuristic algorithm 202312476220  
promising network architecture that can provide better communication and more scenarios for users. With the development of 6G, satellite networks will also experience new changes and opportunities, bringing new possibilities for the future communication industry [3]. There are three categories to classify satellite networks, which are based on the orbit altitude: low Earth orbit (LEO) satellite networks, medium Earth orbit (MEO) satellite networks, and geostationary Earth orbit (GEO) satellite networks [4]. Recently, LEO satellite constellations have emerged as a significant technology capable of enhancing communication. Satellite networks have the ability to compete with ground networks owing to the higher speed of inter-satellite links (ISL), which surpass the capabilities of optical fibers used in ground networks by reaching the speed of light in a vacuum [5]. In addition, operating at an altitude of 2000 km above the Earth's surface, LEO satellites can significantly reduce the round-trip time (RTT) and waiting time, contributing to their advantage of low latency. However, the dynamic nature of LEO constellations presents new challenges that need to be overcome. The next-generation Internet, based on terrestrial networks and mega-satellite networks, is rapidly growing as an up-and-coming future network with the development of commercial satellites such as Starlink, OneWeb, and Telesat [6]. LSNs offer key advantages over terrestrial network solutions, including global network access, low deployment costs, and 24/7 availability. Moreover, LSNs provide lower communication latency and higher data rates compared to GEO and MEO satellite communication systems [7]. The advantages of LSNs make them a crucial infrastructure in the development of the next generation of space-air-ground integrated networks. Given the LSN's ability to support a range of applications, including telecommunication, remote sensing, location, and navigation, it is essential to enhance the performance of LSN facilities in response to their dynamic topology. The issue of routing strategy and ground station geographic planning is inevitable [8] in LSNs; the former controls the transmission of traffic and the latter improves LSN performance by ensuring satellite coverage [9]. LSNs exhibit different behavior compared to terrestrial networks due to several factors. Firstly, the mobility of satellites causes frequent variations in the network topology.