Abstract: DC power grid technology puts forward new requirements for equipment. High-voltage DC circuit breakers with fast breaking capability are the core equipment of DC power grids. However,the existing test technology fails to meet the short-term current tolerance requirements of DC circuit breakers in terms of power. To this end,this paper analyzes the shortterm current stress tolerated by the DC circuit breaker in the DC grid,proposes a test method and test circuit topology based on the loss and junction temperature equivalence and builds a PSCAD/EMTDC electromagnetic transient simulation model.Taking the Kangbao Station of Zhangbei Project as an example,the short-term current withstand test of the DC circuit breaker was simulated and verified. The simulation results show that the test circuit can effectively implement the short-term current stress assessment of the DC circuit breaker,providing guidance for the design of the test platform.