Abstract: At 15:48 on March 21, 2018, a large-scale blackout occurred in Brazil, the power grid in the north and northeast of Brazil were disconnected from main power grid. The load shedding was 19760 MW, accounted for 25% of the total load of the power grid, and 85% of the states were affected, resulting in huge economic losses. In order to avoid severe large-scale blackouts, the main process of blackouts in history was introduced, and lessons learned from blackouts were summarized from the aspects of natural conditions, equipment faults, manual mistakes, strategic mistakes and so on. The main causes of large power outage accidents were analyzed and the corresponding measures were put forward. Finally, combined with several development and research highlights of current power systems, such as renewable energy integration, AC/DC hybrid power systems, energy internet, cyber-physical power systems, and artificial intelligence, the main research directions of power system large scale blackouts were proposed.