Karst ecosystems are fragile and constantly faced with ecological degradation. This study constructed a multi-scale ecological network adapted to the characteristics of karst areas by taking Qujing City in Yunnan, China as a case study, providing a scientific basis for regional ecological restoration. Incorporation of rocky desertification sensitivity factors into landscape resistance surface construction improved the network's ability to reflect the ecological characteristics of karst areas. Ecological sources were identified and landscape resistance surfaces were constructed at both Municipal and metropolitan scales. Least-cost path models and circuit theory were applied to identify the ecological corridors, key nodes, and ecological barriers. The analysis results demonstrated that the ecological sources of Qujing are mainly distributed in the east and south parts, with sparse distribution in the central and western parts. In addition, the research identified 154 Municipal-scale and 67 metropolitan-scale ecological corridors, which are distributed in a 'dendritic' pattern. High-resistance areas are primarily distributed around the built-up and rocky desertified areas. Multi-scale nested analysis revealed the interaction mechanisms between ecological elements at different scales. Based on the findings, we propose an ecological security pattern of 'Two Belts, Three Shields, and Multiple Corridors', providing a foundation for formulating differentiated ecological restoration strategies for karst areas. Overall, this study offers a new method and perspective for constructing multi-scale ecological networks in karst areas, which is significant for the promotion of regional ecological security.