Abstract: This study utilizes chemical kinetics simulation technology to systematically investigate the combustion and explosion characteristics of aluminum-magnesium (Al–Mg) alloy powders with varying magnesium contents (10%, 20%, 30%, 40%, and 50% mass fraction). It employs a zero-dimensional closed homogeneous reactor model in Chemkin to conduct numerical simulations of the combustion process of Al–xMg alloys. The analysis focuses temperature evolution patterns, the generation and consumption dynamics of key free radicals (·O, AlO, and Al₂O), and the evolution mechanisms of oxidation reaction pathways. It further evaluates the influence of Mg content on the reaction rate and productivity of Al–Mg alloys, thereby clarifying the role of the Mg content in the explosion process of Al–Mg alloys at various kinetic levels and gaining a better understanding of the explosion behavior of Al–Mg alloys. The results show that the Mg content significantly influences the combustion and explosion characteristics of Al–Mg alloys; the higher the Mg content, the more intense the alloy reaction. The combustion and explosion of Al–Mg alloys occurs via three stages; in the initial stage, the high reactivity of Mg causes it to rapidly react with oxygen to form MgO, while Al reacts with the remaining oxygen to generate intermediate products such as·AlO/·Al₂O. Subsequently, AlO/·Al₂O reacts with ·O free radicals, ultimately converting to Al₂O₃. A comparison of the reaction kinetic pathways of Al–10%Mg and Al–50%Mg powders showed that the number of reaction pathways of the Al–50%Mg powder was relatively low. Among them, the main reaction pathways of ·Al free radicals decreased from three to two, thereby reducing the number of pathways for generating the intermediate product·Al₂O. This reduction arises from oxidative competition between Mg and Al during the combustion and explosion processes. The entire process occurs in a closed container. Owing to the stronger chemical activity of Mg compared to Al, Mg preferentially reacts with oxygen in the container, leading to a reduction in the concentration of ·O free radicals in gas phase and weakening of the Al–O reaction. The higher the Mg content, the more O free radicals are consumed. Therefore, when the Mg content increases to 50%, ·Al can only react with the remaining·O to form·AlO and·Al₂O; it cannot be further oxidized to form·AlO₂. Similarly, the main reaction pathway for AlO decreases from four to three. In terms of the reaction rate, the Mg-based elementary absolute rate of production was higher in Al–50Mg powder compared to that in Al–10%Mg powder. Notably, the rate of the Mg–O reaction increased threefold, whereas the Al-based elementary reaction rate declined. This phenomenon is attributed to the increased Mg and reduced Al contents. The increase in the decomposition reaction rate of AlO further indicates that the addition of Mg promoted the AlO decomposition reaction and, to a certain extent, accelerated the formation of Al₂O. In addition, during the combustion and explosion of Al–Mg alloys, temperature rise was dominated by the elementary reaction between Al and ·O; the addition of Mg suppressed the Al–O reaction, thus decreasing the overall reaction temperature with increasing Mg content. The reaction kinetics of Al–Mg alloys revealed microscopic changes in chemical substances during the combustion and explosion processes. These research findings provide a theoretical basis for the selection of Al–Mg alloys and for the prevention and control of combustion-explosion accidents during industrial production.