The invention discloses an electrical partition-based electromagnetic loop network-containing critical transmission section search method, which comprises the steps as follows: power network parameters are obtained; an impedance matrix of a system is formed after voltage grade reduction; the system is a power system; all systems hereinafter are the power systems; electrical partitioning is carried out on an actual power network; partition sections between various electrical partitions are searched; the partition sections are combined to obtain electromagnetic loop network-containing transmission sections; the criticality of the transmission sections is defined; and calculation sorting is carried out on the criticality of various sections to obtain the critical transmission section. The critical transmission section search method disclosed by the invention well adapts to electromagnetic loop network-containing transmission section search.