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In the arid and semi-arid region in Northwest China, the pattern of ecological land use is an important guarantee to maintain the regional ecological environment security and stability. Ecological network construction is of great significance. Accordingly, based on the typical ecologically vulnerable area—Dengkou county, remote sensing image interpretation data in 2015 is used as research material. The MCR—P model is constructed, and then the ecological sources, corridors and nodes in county scale are extracted. The Voronoi graph model is introduced into the study of layout of ecological nodes. Blind-zone centroid-based scheme model is constructed and ecological node layout is optimized. The results show that totally 391 ecological source nodes and 667 potential ecological nodes are extracted in Dengkou county. The number of nodes that need to be optimized are 182. After optimization, the coverage rate (CR) of ecological nodes is 87.79%, which is increased by 22.56% compared with the current ecological node coverage rate. The node distribution uniformity (U) is reduced to 0.3978, and the node space distribution is more uniform. After optimization, the covering area of ecological node is 187003hm2, and the area of blind area of Tyson polygon is reduced to 117927hm2, which is reduced by 48446hm2. The structure and node coverage circle space tend to be contiguous, ecological network structure optimization is more stable. The BCBS model constructed by this research can improve the coverage rate of ecological nodes, which is a convenient and efficient method for the layout of regional ecological nodes. This study can provide a scientific basis for construction and management of current and future ecological security pattern.