The frequency of extreme events (e.g., hurricanes, earthquakes, and floods) and artificial attacks (cyber and physical ones) has increased dramatically in recent years, and these events have severely affected power systems ranging from long outage times to major equipment destruction. To reduce the economic loss and social impact caused by power failure, it is of significance to build highly resilient power systems with defense, adaptability, and restoration ability. First, the basic concept and main characteristics of power system resilience are elaborated, and the differences among power system resilience and reliability, security, robustness are compared. Secondly, a framework of resilience evaluation from disaster modeling to system response is constructed, and the resilience index system is reviewed comprehensively, while two categories of resilience indices for static and dynamic assessment are considered. Further, the key technologies of improving the power system resilience are discussed from the three aspects of fault prevention, response, and recovery. Finally, the potential research directions of power system resilience are prospected.This work is supported by the General Program of National Natural Science Foundation of China (No. 51877154).