Background  Biological soil crusts (BSCs) which has unique physiological characteristics and various ecological functions, play an important role in maintaining the stability of the ecosystem. With the deepening of desertification in China, the process of ecological restoration research should be gradually accelerated. Biological soil crusts are the pioneer group of ecological restoration under many extreme environmental conditions, and it is particularly important to grasp the research process, current hot spots and future directions of biological soil crusts

Methods  In this paper, the research hotspots in different period were determined by analyzing key words, journals, core authors and institutions of BSCs research literature in CNKI and Web of Science databases using CiteSpace and VOSviewer. In CNKI, searching pattern was SU='biological crusts' or SU='crusts' or SU='biological soil crusts' or SU='algal crusts' or SU='moss crusts' or SU='lichen' or SU='mixed algal-moss crusts'. In Web of Science, searching pattern was TS='biological soil crusts' OR 'biological crusts' OR 'biocrusts' OR 'moss biocrusts' OR 'cyanobacterial biocrusts' OR 'lichen biocrusts'. Then we screened the search results one by one to select the sample literatures suitable for the research topic by removing conferences, announcements, news, and literature that are not relevant to the research topic.

Results  1)"Composition and diversity of biological soil crusts" "Ecophysiological response of biological soil crusts to environmental stress" "Biological soil crusts and soil hydrological processes" "Soil and water conservation effects of biological soil crusts" "Artificial cultivation of biological soil crusts and ecological restoration practice" were hot spots in different period. 2) Focusing on the response and mechanism of BSCs to environmental stress in different climate regions, the research area gradually expanded from arid and semi-arid desert sand areas to alpine desert areas, semi-arid, semi-humid areas, humid areas and rocky desertification areas, and the research scale had changed from local to regional and global scales.3) The number of published papers increased rapidly since 2002. the research results of authors were mainly published in Chinese journals such as Journal of Desert Research, Acta Ecologica Sinica, and Journal of Soil and Water Conservation, and in English journals such as Catena, Geoderma, Soil Biology and Biochemistry, and Plant and Soil and Science of the Total Environment.

Conclusions  Future research may focus on the following aspects: 1) The research on biological soil crusts will be cross-integrated with other disciplines, such as molecular biology, to break down disciplinary barriers and develop in a coordinated way. 2) The process of scientific research is more closely integrated with modern technologies, such as information technology, medical technology, biotechnology, etc. 3) The scientific research goal will be based on practical application, and will have a deeper research and analysis on the application of artificially cultivated BSCs in soil and water conservation and ecological restoration.