Abstract: Objective Xichang City is a high-risk area of forest fire in China, and establishing a forest fire obstructing network is the most effective way to prevent and control forest fires. According to the relevant standards and specifications, the regional natural geographical elements and existing fire prevention infrastructure that can comprehensively affect the occurrence and development of forest fires were studied. With the help of GIS spatial analysis, a suitable spatial location of the integrated forest obstructing network is proposed to provide a reference for improving the forest fire obstructing network in Xichang City.Method By analyzing the forest fire risk level, the effective obstructing network density and control area were determined. The geostatistics and hydrological analysis, SVM (support vector machine), and factor correlation analysis were used to obtain main factors affecting the layout of the forest fire comprehensive obstructing network. Then, based on various factors and current conditions, in terms of the principles of efficiency, ecology and cost, the cost factor weight analysis was used to quantitatively select the location for the spatial layout of the comprehensive obstructing network. Finally, the potential for spatial optimization was analyzed based on natural geographical factors and existing fire prevention and obstructing facilities.Result 1) During the forest fire prevention period in Xichang City, the highest fire risk level is set as Level I. The effective density of the comprehensive obstructing network should be greater than 17.88 m·hm^–2, and the control area should be less than 500 hm². The existing obstructing does not meet the standard requirements. 2) The factors selected through research are closely related to the layout of forest fire obstructing. Multi factor characteristics are taken into consideration to make the layout of the obstructing network more comprehensive and complete. 3) The natural obstructing network is suitable for layout on ridges, valleys, rivers, and waters that meet the width and orientation, and mainly distributed in the southeast and northeast mountains of Xichang City and around Lushan Mountain. The biological obstructing network can be arranged at forest edges and in open spaces suitable for afforestation, and mainly distributed in the periphery and interior of large areas of forests and around forest settlements. The engineering obstructing network is suitable for low cost areas such as low wind speed, slope, and bare land with low altitude. 4) The suitable area of the comprehensive obstructing network in Xichang City can basically cover the existing forest land, and effectively block flammables from concentrated forest area. The existing forest fire obstructing layout in the northwest and southeast regions is relatively weak, and the construction of the comprehensive barrier network should be strengthened according to local conditions.Conclusion The layout and function of the existing fire obstructing network in Xichang City are not perfect, and a scientific obstructing system should be established by comprehensively considering various relevant factors and actual conditions. This study quantitatively and visually analyzes the layout of the comprehensive obstructing network in Xichang City, which has practical significance for improving the regional fire prevention and extinguishing capacity, maintaining ecological security, and has certain reference value for related networks planning.

Key words: forest fire, comprehensive obstructing network, GIS, spatial distribution, Xichang City