Abstract: In order to investigate the ignition mechanism of composite solid propellant under waterjet high pressure from the dust ignition mode perspective, the modified Hartman bomb device was used to study experimentally the minimum explosive mass concentration of AP/Al/ferrocene mixed system. Processes of dust explosion of the typical composite propellant were discussed. Effects of components, temperature and humidity on the minimum explosive mass concentration were investigated. Results show that the minimum explosive mass concentration increases with the increase of humidity, while it decreases with the increase of temperature. Also, the minimum explosive mass concentration of the mixed system is sensitive to the content of AP/ferrocene.