This study investigates the adverse effects of moisture to the energetic materials using Zirconium (Zr) and Iron (III) oxide (Fe2O3) as energy sources. The moisture thermally decreased the heat of reaction and made the reaction difficult by increasing the activation energy. By using the X-ray photoelectron spectroscopy (XPS), decomposition of oxidizer, Fe2O3, and formation of ZrO2 process was investigated. Finally, Transmission Electron Microscopy-Energy-Dispersive X-ray Spectroscopy (TEM-EDS) and Fast Fourier Transform (FFT) image analysis were used to analyze the Zr surface in depth, which is the main energy source. Moisture acted on the surface of Zr to directly form oxide layer and ZrO2, as well as generating cracks on the surface, allowing penetration of oxygen to the deep inside. As a result, moisture was the critical factor of natural aging and has adversely affected both the oxidizing agent, Fe2O3, and the energy source, Zr. © Asia-Pacific Conference on Combustion, ASPACC 2019.All right reserved.