Taking Nagqu county in the alpine pasture of Tibetan Plateau as a case study, this paper built a land suitability evaluation index system of settlements, assessed the suitability of the land for the layout of settlements and its suitability grade in the study area using self-organizing mapping neural network (SOFM), evaluated the land suitability of current settlements, and further explored the paths of settlement reconstruction. The results showed that: (1) Nagqu county had a low level of land suitability for the layout of settlements. Suitable and sub-suitable areas, scattered in valleys with low elevations and flat terrain, only accounted for 12% of the total land area. Other areas of poorer suitability were relatively concentrated, accounting for 88% of the total land area. There were obvious differences among various townships and towns in the land suitability of settlements. (2) The current settlements of Nagqu county covered an area of 75.94 km2, accounting for only 0.47% of the total land area. Areas where the suitability level was generally suitable and above accounted for 86.47%. About 13.53% of settlement area was distributed in hardly suitable, unsuitable, or prohibited construction areas. The layout of settlements in various townships and towns tended towards high-grade suitability areas. The better the environmental conditions, the more reasonable the layout of settlements; and vice versa. Lack of planning guidelines, irrational setting of administrative villages, local identification with specific survival spaces, and worshipping of mountains by Tibetans all contributed to the unreasonable layout of settlements in Nagqu county. (3) Ecomigration, "village-oriented" development in suitable areas, and other promotion factors can be integrated to realize the spatial reconstruction of settlements. Through constructing the central villages and towns system supported by characteristic industries and giving full play to the element diffusion role of the "point-axis" system, restructuring can be promoted to achieve the economic restructuring of settlements. By means of improving the allocation of public service facilities, enhancing the degree of social organization, strengthening the inheritance of Tibetan culture, and promoting the optimization of other functions, the social restructuring of settlements will be accomplished.