The invention discloses a method and a device for monitoring the crossing of direct current insulated buses. The method comprises the following steps of arranging two sections of independently running direct current buses on two direct current ground insulation monitoring devices respectively; performing connection according to a direct current crossing mode, inputting the balanced bridge resistance of the two direct current ground insulation monitoring devices into the other direct current ground insulation monitoring devices, and monitoring the ground resistance of each other by using the direct current ground insulation monitoring devices; arranging a group of communication cables between the two respectively running direct current ground insulation monitoring devices for data communication; receiving related measurement data acquired by acquisition modules through the communication cables by using the two direct current ground insulation monitoring devices respectively; judging whether direct current crossing corresponding to the direct current bus crossing mode occurs or not according to the measurement data. According to the method and the device, whether the direct current crossing occurs or not can be accurately monitored, an alarm about a direct current line to which the direct current crossing occurs is given, and a loop in which the two sections of direct current buses are crossed can be accurately found.