The characteristic of phononic crystals local resonance was applied to beam to form a local resonat beam. Based on local resonant beam, and by introducing analogy lattice parameter mismatch, a local resonance model of detuning beam was obtained. Through sine excitation response analysis and frequency response analysis of local resonance periodic beam and detuning beam respectively, and combined with the improved energy method, it can be concluded that, by choosing the appropriate detuning parameters，detuning beam is better than periodic beam in the characteristics of vibration reduction.