Rural settlements serve as spatial carriers for studying human-land relationships in rural areas, and their layout optimization constitutes a crucial approach to promoting comprehensive rural revitalization. Using the rural settlement patches of Salaxi Town in Qixingguan District, Bijie City-a typical karst mountainous town-as a case study, this research examines the impacts of growth poles (areas with concentrated development vitality) and development axes (transport networks) on rural settlement spatial distribution. The findings indicate: ① Significant variations exist in the spatial distribution of development vitality across rural settlements in Salaxi Town, predominantly concentrated in the Sala Community, Chongfeng Village, Shuijinggou Village, Shuanglong Village, Longchang Village, and Gezuo Village; ② Rural settlements in Salaxi Town can be categorized into four optimization types: urban-rural integration, clustered development, relocation and consolidation, and improvement-oriented development; ③ The rural settlements in Salaxi Town can be categorized into four major optimization zones: the Economic Center Zone, the Rural Restructuring Zone, the Relocation and Consolidation Zone, and the Secondary Center Zone. Through spatial guidance and integration strategies tailored to different optimization types, this study provides reference insights for scientific planning of rural settlements in karst mountainous towns.

The objective of this study was to identify the zoning types for the rural settlement improvement in the Wumeng Mountains. The recognition criteria were established to implement the differentiated strategies. Territorial spatial planning was fully integrated with the rural revitalization for high-quality rural development. The research subject was taken as the rural settlements in Hezhang County, Guizhou Province, China. Firstly, the GIS spatial overlay analysis was utilized to preliminarily explore the spatial distribution relationships between rural settlements and permanent basic farmland, urban development boundaries, and ecological protection red lines, according to the rigid constraints of the “Three Zones and Three Lines” in the territorial spatial planning. Subsequently, an evaluation index system was developed for the rural settlement land suitability over three dimensions: natural conditions, ecological security, and infrastructure conditions. Indicator weights were calculated using the Analytic Hierarchy Process (AHP) and entropy weight. An evaluation model was constructed to quantify the rural settlement land suitability index. Finally, the constraints of the “Three Zones and Three Lines” were integrated with the land suitability. A national standard was established to identify the rural settlement improvement zones in order to facilitate the zoned improvement efforts. The results revealed that: 1) Rural settlements in Hezhang County exhibited a spatial density pattern with the “high density in the central area and low density in the north and south.” Settlements that interacted with the permanent basic farmland, ecological protection red lines, and urban development boundaries were classified into three types: the agricultural security type, the ecological conservation type, and the urban development type, accounting for 0.01%, 0.59%, and 8.83% of the total rural settlement area in the study region, respectively; 2) According to the natural breakpoint, the suitability index of the rural settlement land use was categorized into four levels: extremely unsuitable, unsuitable, suitable, and extremely suitable. Spatially, there was a “highly suitable in the center, unsuitable at both ends” distribution pattern. The area of each suitability level shared an initial increase followed by a decrease; 3) According to the Hezhang County's requirements to preserve the historical culture and distinctive tourism resources, the interaction between settlements and the “Three Zones and Three Lines” framework, and land suitability ratings, rural settlements were categorized into the priority development zones (49.13%), improvement and enhancement zones (28.86%), urban integration zones (8.55%), relocation and consolidation zones (10.19%), and special protection zones (3.27%). The areas of different zones also exhibited a linear decreasing pattern. Tailored remediation strategies, including village clustering, industrial development, and living environment improvement, were formulated for each zone based on their unique settlement characteristics. This finding can also provide valuable case references and practical pathways for the precise territorial planning and dynamic optimization of village layouts in mountainous regions.