The invention relates to a high-voltage DC circuit breaker, which comprises a plurality of circuit breaker power assemblies and arrester assemblies, wherein the plurality of circuit breaker power assemblies are sequentially connected in series and are arranged by layers at intervals along the up-down direction; interlayer support insulators are arranged between any two adjacent layers of circuit breaker power assemblies to form a valve tower main body; and the arrester assemblies are correspondingly arranged beside the valve tower main bodies. According to the high-voltage DC circuit breaker provided by the invention, the plurality of circuit breaker power assemblies are arranged by layers at intervals along the up-down direction; interlayer support insulators are arranged between any two adjacent layers of circuit breaker power assemblies to form one valve tower main body; and the plurality of circuit breaker power assemblies are arranged by layers along the up-down direction, so that the arrangement is relatively compact; and the horizontal floor area is relatively small.