Abstract: On March 21, 2018, during the power grid failure, the Brazilian national power grid (sistema interligado nacional, SIN) was disintegrated into 3 islands: the Northern, the Northeastern, and the Southern power grids were in independent operation modes with the power supply of 23 states affected and 26% load of the whole power grid lost. The dispatching departments, together with a plenty of power plants, transmission companies and distribution companies nationwide, tried to restore the power supply in time. The restoration was divided into two steps. The first step was to restore power supply with loads inside the 3 independent operation grids themselves. The second was to realize the interconnection between the 3 independent operating power grids, strengthen their mutual supports and take anti-measures to avoid the risks of another failure. After the blackout, the Southern power grid basically maintained its structural integrity, and the restoration process mainly focused on the voltage control and the rapid load restoration. Thanks to the 2 power plants keeping operations, the North power grid configured 4 recovery work-interfaces to restore the power supply gradually. The Northeast power grid had to conduct a black-start by configuring 6 recovery work-interfaces with the help of its 5 power plants with self-start capabilities in order to restore the power supply. Although the restoration process of the overall power grids were basically timely and orderly, some difficulties were encountered, including differences between on-site operations and dispatching commands, operating difficulties of both the closing loop and integration into the grid resulting from the system oscillation and the large-scale free shifting of power flows, failures of the supervision and communication systems, the breaker operation abnormalities, auxiliary power supply failure, self-starting anomalies of the generators, etc. It shows that some aspects should be considered aiming to optimize and improve the power grid restoration and reconstruction, including planning and maintenance of the power plants, the power grid structure configuration, and equipment maintenance, dispatching management and implementation, and so on.