In the context of climate change,the frequency and impact of drought at global scale is in an increase trend. As a scientific foundation and basis for disaster prevention and relief,the research on drought risk assessment has attracted widespread attention both at home and abroad. Drought risk assessment at national and regional scales started earlier and deeper,yet drought risk assessment at global scale is currently at the beginning stage. In this paper,a systemic review was carried out at the aspects of data sources,basic units,index system,risk assessment models,and case studies of global drought. Our findings indicated that a significant progress of drought risk assessment at national and regional scales has been achieved,which could provide the valuable references for drought risk research at global scale. With the development of quantitative study on drought hazard and socio-economic vulnerability assessment,drought risk research at global scale is currently in a holistic trend of multi-index integration with an increasing number of quantitative assessment models. The drought assessment indicators tend to be constructed based on a multi-source dataset and multi-factor integration. It is important to develop more quantitative models for drought risk assessment. It is of great significance to explore and work out a set of vector units. Future drought risk assessment at various spatiotemporal scales should be carried out based on the quantitative construction of vulnerability curves so as to provide more scientific references for drought risk governance all over the world.