Abstract: Substation DC system could provide control and power supply for electrical equipment, but the selection of DC circuit breaker mostly depended on engineering design experience, was lack of the relevant provisions of the range matching test, which was easily to produce leap-level trip phenomenon and expand the range of accidents.In view of the above hidden problems, this paper introduced a stage difference coordination verification method based on ampere-second characteristic curve of circuit breaker, and took the 220 kV indoor, outdoor and semi-indoor DC systems as examples to build a test platform for circuit breaker stage difference coordination testing.The test results showed that for the second level circuit breaker, 100 A could meet the requirements of load current and stage difference coordination.Finally, the paper put forward the general proposed selection scheme of DC circuit breakers in 220 kV substations in the Hebei Southern Grid area.