The invention provides direct current ground fault isolation equipment and a system. The equipment comprises insulation monitoring devices and a switching device group; a first insulation monitoring device is respectively connected with multiple switching devices and a main bus; a second insulation monitoring device is respectively connected with multiple switching devices and a spare bus; when aload branch circuit group is connected with the main bus by virtue of the switching device group, the first insulation monitoring device is used for monitoring direct current ground information of theload branch circuit group and judging whether the load branch circuit group is in a direct current ground fault according to the direct current ground information; and when the load branch circuit group is in the direct current ground information, the second insulation monitoring device is used for monitoring each load branch circuit, determining the load branch circuit where the direct current ground fault occurs and isolating the corresponding load branch circuit where the direct current ground fault occurs. A fault branch circuit is determined by adding the spare bus, and the fault branchcircuit is isolated, so as to reduce difficulty for finding the fault branch circuit and improve security of an electric power system.