Abstract: A variety of hybrid high voltage direct current (HVDC) circuit breakers were developed worldwide and have been successfully put into operation, which have broad application prospects in multi-terminal and DC power grids. Short-circuit current breaking capability is the core performance of DC circuit breakers (DCCB). However, large current, high voltage and huge energy appear simultaneously during the breaking process, which makes it extremely difficult to reproduce the equivalent breaking stress in the laboratory. So far, there is still no uniform international standard for the breaking test, and lack of theoretical research and calculation on the relationship of test capacity and equivalence. Based on the breaking principle of hybrid DCCBs, this paper analyzed the equivalent stresses at each breaking stage, and revealed the mathematical relationship on test capacity and equivalence which supporting the test parameters design and equivalence analysis. Then a dual-frequency current source synthetic breaking test method was proposed, and the key stress mathematical analysis and the test circuit parameters optimal design were achieved. Finally, simulation and comparative analysis for the test stress and equivalence were carried out. The research shows that the dual-frequency current source synthetic test method can realize the full equivalent of the breaking electrical stresses of hybrid DCCBs with good economic performance, and have great guiding significance for the equipment development and standards formulation of hybrid DCCB breaking test.