The invention provides a large power grid on-line data multi-thread rapid-integration method. The method comprises the steps of 1) reading and parsing various types of power grid data, storing the power grid data into an internal storage, and partitioning the internal storage according to the power grid data of power grid equipment of different types; 2) employing a parallel processing mode to associate the power grid equipment in each internal storage part after the partition with a corresponding topology node and establishing an association topology node list with respect to the topology nodes; and 3) zoning the topology nodes corresponding to the internal storage parts based on the partition of the internal storage, employing the parallel processing mode to conduct traversal analysis of the association topology node list of the topology nodes in each zone, performing topology island numbering of each topology node, eliminating dead topology islands, determining cared topology islands, conducting topology merging of all the zones of the topology nodes through tie lines among the zones of the topology nodes, and generating integrated power grid on-line data. The power grid data integration method provided by the invention is high in integration efficiency and rapid and highly efficient in processing procedure.