The invention relates to a DC power supply switching device and a DC power supply. The switching device comprises a first control loop, a second control loop, a first voltage monitoring relay and a second voltage monitoring relay, wherein the first control loop is used for switching a first DC power supply incoming line, the second control loop is used for switching a second DC power supply incoming line, a coil of the first voltage monitoring relay is used for connecting the first DC power supply incoming line, a coil of the second voltage monitoring relay is used for connecting the second DC power supply incoming line, a normally-open contact of the first voltage monitoring relay and a normally-closed contact of the second voltage monitoring relay are connected in parallel and then are arranged in the first control loop, and a normally-open contact of the second voltage monitoring relay and a normally-closed contact of the first voltage monitoring relay are connected in parallel and then are arranged in the second control loop. By connecting in parallel the normally-open contacts and the normally-closed contacts of different voltage monitoring relays, the problem that the two DC power supplies cannot be put into use caused by faults occurring in the two voltage monitoring relays is prevented.