To improve the stability of aluminum hydride （AlH₃）， three kinds of embedded-coated AlH₃@Al@xAP（AHAPs） energetic composite particles were prepared by the combination of using acoustic resonance and spray drying technology. The mass ratios of AlH₃@Al and AP were 9∶1（AHAPs-10%）， 7∶3（AHAPs-30%）， and 1∶1（AHAPs-50%）， respectively. The morphologies and structures of the AHAPs and their condensed combustion products were characterized by SEM， EDS， and XRD. The thermal reactivity and stability of the prepared samples were comparatively studied by TG-DSC analysis and vacuum stability tester （VST）. Results show that AHAPs energetic composite particles could not only improve the stability of AlH₃ but also promote the decomposition of AP. With the increase of AP content， the initial decomposition temperatures of AlH₃ are increased by 8.5-11 ℃， and the peak temperature at high-temperature decomposition stage of AP is decreased by about 80 ℃. Compared with the total decomposition time of pure AlH₃（1006 min）， the decomposition time of AHAPs-50% composite particles extend to 1518 min， which corresponds to a 50.9% increment. In addition， the reaction heat of embedded-coated composite particles AlH₃@Al/63.5% AP reaches 9125.6 J·g^-1， which is 1054.1 J·g^-1 higher than that of mechanically mixed samples， and the particle sizes of the condensed combustion products appear to be finer， indicating that their combustion become more complete and the combustion efficiency is greatly enhanced.