The invention relates to a load characteristic-based classification low-voltage load shedding method and system. The load characteristic-based classification low-voltage load shedding method comprises the following steps of 1) analyzing dynamic response characteristic of a load to obtain a Q-V relation characteristic curve of load reactive power changing with a voltage; 2) making an initial low-voltage load shedding scheme according to an existing method by taking a dynamic motor load as a basic load; 3) determining replacement parameters of the load under different voltage levels according to the Q-V relation characteristic curve; 4) proposing a mode of configuring the classification low-voltage load shedding measure to remove each load capacity according to the replacement coefficients; and 5) verifying and determining a final classification low-voltage load shedding scheme by simulation calculation. The technical scheme lies in that the defect of an existing low-voltage load shedding measure is made up, and a risk of large-area failure of a power grid is reduced.