The construction of ecological security pattern in vulnerable ecological region is essential to maintain regional ecological security. The traditional methods of constructing ecological security patterns mostly take static ecological indicators as the basic indexes and give less consideration to the migration processes of major species, which easily ignore areas with low ecological services and species abundance but important for species migration, resulting in functional loss of habitats. Therefore, taking Shigatse as an example, this paper identified ecological sources based on the evaluation of habitat suitability and constructed an index system for ecological resistance evaluation in terms of topography and land use. We used the minimum cumulative resistance model (MCR) to identify ecological corridors, took the intersection of ecological corridors and resistance ridges as ecological nodes, and then constructed an ecological security pattern by combining the spatial characteristics of ecological services. Results indicate that:(1) the ecological source of Shigatse covered an area of 82588 km², accounting for about 46% of its entire territory. It was mainly distributed in the southern gorge area, the central valley area of Yarlung Tsangpo River and the northern alpine area, with grassland, water, woodland and unused land as the main land types. (2) The cumulative length of ecological corridors was 5,135 km, which were distributed in a network, linking the city's important habitats closely, and were similar to the ecologically spatial distribution in the city. The corridors were mainly distributed along rivers and mountains. During the construction of corridors, attention should be paid to the greening of both sides of the water and the ecological protection of the mountains. (3) Ecological nodes are key points with weak ecological functions, and their protection should be strengthened to improve their connectivity. In this study, a total of 67 ecological nodes were identified, which were mainly distributed in the southern border area, mainly the unused land. (4) We proposed to build an ecological security pattern of "two screens, one watershed" to ensure the ecological security of Shigatse. Among them, "two screens" referred to the middle of the Himalayas ecological barrier area (MHEB) and the Gangdise-Nyainqentanglha Mountains ecological barrier area (GNEB), and "one watershed" referred to the middle and upper reaches of the Yarlung Tsangpo River (MUYT). The MHEB should give full play to the role of the overall ecological barrier, and focus on promoting the protection of wild animals and plants and the construction of protected areas. The GNEB should strengthen the conservation of water resources of the ecosystem and the protection of biodiversity functions. The MUYT should focus on the integrated management of land subject to erosion and desertification. With an area of 51,730 km², accounting for about 29% of the total Shigatse area, this area could support the habitat and migration of 12 species and protect 72.0% of the critical area for water conservation, 69.9% of the critical area for soil conservation, 57.5% of the critical area for wind and sand control, and 99.6% of the critical area for carbon fixation. The use of ecological corridors and ecosystem services to construct regional ecological security patterns can provide decision-making tools for ecosystem and species conservation in vulnerable areas.