Chemical reactions are governed by the potential energy surface (PES), the function of Euclidian coordinates of N atoms. In a chemical sense, local minima, or equilibrium structures (EQs), of PES correspond to stable conformers, which share the atomic constitution, but have different structures with each other. The first-order saddle point, connecting two EQs, is known as the transition state (TS) of chemical reaction converting these EQs. The potential energies of EQs and TSs on PES primarily determine the entire reaction properties.Recently, GRRM program has enabled the automatic construction of the collection of EQs and TSs on PES, called the reaction route map (RRM). An RRM can be regarded as an energy-weighted network graph, where each EQ and TS correspond to a node and an edge, respectively. GRRM has led to an understanding of the reaction mechanism of the system by using RRMs. However, studies of reaction mechanisms to date have only considered a subset of TSs with low activation energies and the EQs connected to them, and have not focused on the full picture. Concentrating on this whole may create new value.We extract features of RRM by using Persistent Homology, an analysis based on "hole" information. By using this method for RRMs of metal nanocluster systems, we found that clusters of similar composition return similar PDs. This may allow for predictions of reactivity based on RRMs.