Abstract: The experimental research on structural damage alarming of Benchmark structure is performed in this paper based on the structural damage alarming method using wavelet packet energy spectrum. Various damage statuses are simulated through the Benchmark test model, and thus structural dynamic responses are collected with respect to the intact model and damaged models. Based on the collected structural responses, the wavelet packet energy spectrum and corresponding damage alarming indices are calculated. Experimental results reveal that the structural damage alarming indices calculated by the wavelet packet energy spectrum have preferable damage alarming capacity and can effectively detect the structural initial damage.