The invention relates to a real-time short-circuit current monitoring device and monitoring method for an offshore power grid power station. The real-time short-circuit current monitoring device is characterized in that the monitoring device comprises a power supply, a power grid device state gathering module, a central processing unit (CPU), a pre-alarming display module and a load inhibiting drive module, wherein the power supply supplies power for the power grid device state gathering module, the CPU, the pre-alarming display module and the load inhibiting drive module, a power grid device state gathering circuit real-timely gathers on-off state signals of breakers of devices of a power grid, generates a real-time status table, and sends the real-time status table to the CPU, the CPU transmits real-timely obtained short-circuit current to a pre-alarming display circuit, the pre-alarming display circuit real-timely outputs an alarming signal, the CPU transmits produced load inhibiting parameters to a load inhibiting drive circuit, and the load inhibiting drive circuit generates a load inhibiting signal and inhibits starting of a current off-line load. The real-time short-circuit current monitoring device and monitoring method can be widely applied to the offshore power grid power station.