Conductance resonance of a metal-insulator-metal junction with an embedded metal cluster, which has different size and structure, is studied by the generalized Breit–Wigner formula in a tight-binding approximation. We find that a certain metal cluster possesses a specific peak pattern in the conductance data, that is, the conductance resonance peaks depend on the size and structure of metal clusters and the resonant broadening Γ is related to the tunnel barrier parameters. This arrangement can induce a high-quality tunneling structure with very narrow resonance peaks. Therefore, both the size effect and structure effect of the metal clusters can be predicted by observing conductance resonance of tunneling structure of embedding metal clusters in metal-insulator-metal junction. It is also possible to develop some new microelectronic devices with this structure.