Summary: An essentially disconnected hexagonal system is defined as a hexagonal system which has fixed bonds and Kekulé structures. In this paper, an essentially disconnected structure feature is given to recognize an essentially disconnected hexagonal system \(G\): the subgraph obtained by deleting all the fixed single bonds and all the end vertices of the fixed double bonds of \(G\), has at least two normal components, and one of them is normal hexagonal system or normal generalized hexagonal system.