With the development of power electronics technology,the DC power distribution network presents its obvious advantage in technology and economic and has good prospects in the background of an energy revolution.First,the development of low-voltage DC power supply and voltage levels were discussed.Then,it summarizes and analyzes the key technologies of DC distribution network coordination control technology,protection technology and power quality control,as well as the development of key equipment.At last,the project research and application of DC power supply engineering in the world are summarized.The construction of active distribution network in Suzhou industrial park is an important exploration of urban energy transformation.