The invention relates to a main through-flow branch structure of a direct current circuit breaker. The branch structure comprises a framework assembly, multiple groups of main branch valve assemblies, a lightning arrester and a cooling assembly. The main branch valve assemblies and the lightning arrester are arranged on the upper part of the framework assembly. The cooling assembly is arranged on the lower part of the framework assembly. The main branch valve assemblies are parallelly connected to the upper part of the framework assembly and are parallelly connected with the lightning arrester. Each of the main branch valve assemblies comprises an RCD assembly and an IGBT assembly which are electrically connected. Each IGBT assembly comprises a radiator. A water outlet and a water inlet are arranged in each radiator. The cooling assembly comprises a water charging branch pipe and a water discharging branch pipe which are fixed on the lower part of the framework assembly. The water charging branch pipe communicates with the water inlets of the radiators. The water discharging branch pipe communicates with the water outlets of the radiators. The branch structure is compact, proper in layout and capable of achieving cooling.