Rocky desertification in karst landscapes has caused substantial harm to regional ecosystems, necessitating effective restoration methods. Biological soil crust technology, an innovative approach based on microbial ecosystem reconstruction, has shown notable success in combating desertification by improving soil structure, enhancing water retention, and promoting vegetation restoration. This review summarizes the research progress on the application of biological soil crust technology in karst rocky desertification areas, focusing on its ecological roles in soil improvement, erosion control, and habitat stabilization. Furthermore, key challenges related to crust stability, environmental adaptability, and large-scale implementation are discussed, along with future research directions and development trends, to facilitate the broader application and practical promotion of this technology in karst regions and similar fragile environments. The review also outlines the ecological significance of biological soil crust technology in enhancing the resilience and functionality of degraded ecosystems, thereby providing theoretical and technical support for its wider application in global ecological restoration efforts aimed at reversing land degradation and improving ecosystem services.