Brazil ±800kV Xingu convertor station’s technical defects lead to chain reaction in Brazil that a Brazilian nationwide blackout accident happened on March 21st, 2018. This blackout severely impact the north and northeast of Brazil including 14 states. In this paper, the general situation of Brazilian power grid is introduced. And the occurrence and propagation of the blackout are retrospected. Furthermore, the main reason of the blackouts are analyzed in this article. According to the Brazilian blackout, Qishao DC is evaluated from the relay protection, configuration of security and stability equipment and strategy analysis of power plants’ primary frequency regulation. Combined with the reality of Hunan power grid, this paper sum up experience and lessons of Brazilian blackout.