The invention provides a power grid fault processing method and system based on an inverter. The power grid fault processing method based on the inverter comprises the following steps of acquiring thecurrent value of an inverter alternating current side, and determining whether the current value exceeds a preset current-limited setting value; when the current value exceeds the current-limited setting value, making the inverter send a forbidden switching-on signal to a bus section switch and entering into an active voltage control mode; detecting the voltage detection value of a first sectionalized bus, and according to the size relation of the voltage detection value and a preset voltage value, determining the time when the inverter is in the active voltage control mode; and when the timeis less than a preset short-time current limiting time, making the inverter cancel the forbidden switching-on signal. In the invention, when a power grid has a fault, the inverter can be effectivelyprotected, the recognition rate of a bus fault is increased, the enlargement of a fault range and a power failure range is prevented, and then the operation efficiency of the power grid is guaranteed.