The design and fabrication of efficient catalysts for ammonium perchlorate (AP) decomposition is crucial for the performance of composite solid propellants. Herein, a novel hierarchical structure material of Cu-WO 3 nanowire arrays on a nanoflower flake (Cu-WO 3 NANF) was synthesized by a facile hydrothermal reaction. The negatively charged (001) polar facets of hexagonal WO 3 and the action of Cu 2+ induced growth were two important factors for the formation of hierarchical structures. The Cu-WO 3 NANF exhibited remarkable catalytic activity for the thermal decomposition of AP. The temperature and activation energy of high temperature AP decomposition were significantly decreased to 378.3 °C and 147.01 kJ mol −1 , respectively, which are attributed to the more oxygen vacancies and lower band gap energy of the Cu-WO 3 NANF. Thus, it was excited at a lower heat to produce activated species. Under the strong adsorption of Cu-WO 3 NANF surface Lewis acid, the activated species can react with NH 3 quickly and deeply to produce N 2 , N 2 O, NO 2 and NO gases, accompanied by a heat release of up to 1118 J g −1 . The proposed catalytic mechanism was further corroborated by the in situ TG-MS result. This facile strategy provided a new idea for the design of hierarchical catalysts, and our research opened up a new field for WO 3 applications. Cu-WO 3 hierarchical structures are rapidly prepared and they exhibit excellent catalytic activity in AP decomposition due to their rich oxygen vacancies and Lewis acid sites.