The invention provides an overcurrent fault monitoring protection device and method for a flexible direct-current transmission inverter station and relates to the technical field of power system control. The device comprises a microprocessor unit, a composite buffer protection unit, a power frequency conversion unit, an IGBT drive unit, an overheating detection unit, a fault current detection unit, a wireless communication unit, an LC filter and an upper computer, wherein a microprocessor processes the current and temperature information acquired by the overheating detection unit and the fault current detection unit, drives the IGBT drive unit to control the on/off of the IGBT device and transmits the fault information to the upper computer. In the invention, the type of the fault current and the overheating fault of the power frequency conversion unit can be detected and positioned, the detected fault current is positioned, classified and processed so as to quickly and accurately inhibit the short-circuit current and overcurrent in the fault period, the damage of the power frequency conversion unit is avoided, and the monitoring position and protection of overcurrent fault of the flexible direct-current transmission inverter station are realized.