This paper investigates the application of systematic cluster, one of the cluster analysis methods, in the IED switch online condition monitoring. So far, problems still exsit in the IED switch online condition monitoring based on the control system of smart substation. In order to figure out a relatively stable online model and make classification from the online information of IED switch, this paper firstly fliters and preprocesses the online condition information of IED switch, and uses data matrix to describe the online condition of IED switch. Based on this, the paper inroduces a special dissimilarity degree formula to transfer the data matrix into dissimilarity degree matrix, and conducts analysis with clustering pedigree chart out of systematic cluster algorithm. Finally, the paper verifies the feasibility of systematic cluster in the IED switch online condition monitoring.