To investigate the combustion characteristics of ternary active metal fuels Al/B/Mg (ABM) and Al/B/MgH2 (ABM-H), the heat of combustion and minimum ignition energy were studied by using an oxygen bomb calorimeter and a Hartmann tube, respectively. The sub-transient process of flame propagation and the spatiotemporal distribution characteristics of temperature fields were determined by using a high-speed camera system and a high-speed infrared camera system. The results indicate that the calorific values of ABM and ABM-H are 34.1 and 32.2 MJ·kg-1, respectively, exhibiting increases of 14.4% and 8.1% over pure Al (29.8 MJ·kg-1). The minimum ignition energies of ABM, ABM-H, and Al are 160-170, 100-110, and 20-30 mJ, respectively. Compared to pure Al, the combustion duration of ABM and ABM-H increase by 65.5%, 34.5% and the peak flame propagation velocities increase by 12.6%, 23.0%, respectively, at a mass concentration of 625 g·m-3. At a mass concentration of 500 g·m-3, ABM-H and ABM exhibit the largest peak flame propagation velocities by 45.05, 38.7 m·s-1, and the maximum temperatures peak of flame surface by 1856, 1717 ℃, respectively, where ABM-H shows a 7.6% improvement on temperatures peak of flame surface and a faster heating-rate compared to ABM. It suggests that the ABM and ABM-H formulations significantly reduce the explosion risk of the dust/air mixture, and significantly improving the combustion performance. ABM demonstrates superior thermal effects in calorific value and duration of combustion, whereas ABM-H exhibits higher reactivity in terms of minimum ignition energy, flame propagation speed, and temperature rise rate.