Abstract: As a new type of power equipment, there is no relevant test standard for DC circuit breaker currently. Equivalent breaking test scheme needs to be further studied. Compared with AC circuit breaker breaking progress with alternating zero current point, the DC circuit breaker needs to establish transient interruption voltage by the commutation process between different branches, which is higher than the DC system voltage to suppress the fault current. However, voltage-related stress of key components is neglected in existing breaking test in the transient interruption voltage establishment. Firstly, the electrical stress of each key component in the transient interruption voltage establishment was analyzed in this paper. A more detailed and comprehensive evaluation standard for the breaking test of DC circuit breaker was proposed. Then, according to the equivalent parameter k, was proposed in this paper. The test circuit parameter design scheme was carried out by theoretical calculation and simulation analysis. Finally, the experiment was carried out for the 50kV breaker unit, and the experimental result was in line with simulation expectation. As above, value of this paper mainly fills the gap that key electrical stress during transient interruption voltage establishment is neglected in existing DC circuit breaker breaking test. The parameter design scheme of the breaking test circuit provides an economical and feasible solution for the "100%" recurrence of the proposed key stress.