The invention relates to a handling method in the field of electrical power systems, and particularly relates to a graded handling method for faults of centralized operation and maintenance systems. A centralized operation and maintenance system monitors nationally dispatched, individually dispatched and provincially dispatched smart power grids to dispatch data of technical support system working condition type, power grid basic data type, safeguard system type and environment and ancillary equipment type. Aiming at large amounts of data monitored by provincial grid dispatching centers of all levels, for improving the efficiency of fault handling, an operation and maintenance center defines the response times required by removing faults of different levels through grading the faults, and starts handling plans for faults of corresponding levels, so that the real-time handling operation of faults of each level is realized in the operation and maintenance center, thereby reducing the operation and maintenance pressure of a provincial grid dispatching center of each level, and improving the reliability and security of system operation.