Abstract: Mine water contains a large amount of hard water ions, and as the main water used in foam dust suppressants, its water hardness is crucial to the dust removal efficiency and economic costs of foam dust suppressants. In order to study the variation law and microscopic mechanism of foam stability influenced by mine water hardness, molecular simulation was employed to investigate the effects of mine waters containing different concentrations of Ca²⁺, Mg²⁺, and Na⁺ on the stability of foam liquid films. Taking a foam system composed of anionic surfactant Sodium Dodecyl Sulfate (MSDS) and nonionic surfactant Alkyl Ethoxylate (AEO-5) in proportional blending as the research object, the variations in surface tension, interface thickness, radial distribution functions, diffusion coefficients, and hydrogen bonds, which are microscopic characterizations, were thoroughly analyzed. The study reveals several findings. Firstly, the interfacial tension of foam systems increases with higher concentrations of Ca²⁺ and Mg²⁺, particularly under conditions of high water hardness where foam stability is weakest due to thinner interfaces. Secondly, analysis of radial distribution functions and diffusion coefficients indicates that the oxygen atoms of surfactant head groups are crucial for foam stability, with O_1‒3 exhibiting three times greater water adsorption capability compared to O₄. In the presence of Ca²⁺, O_1‒3 and O₄ exhibit stronger water binding capacities within the foam. Thirdly, different ion types exert varying effects on foam stability. Under conditions of moderate to high water hardness and in the presence of Mg²⁺, the average hydrogen bond length between O_1‒3 and water molecules is shorter than that observed with Ca²⁺, suggesting stronger hydrogen bonding in Mg²⁺-containing foams. Conversely, under high water hardness conditions, the average number of hydrogen bonds between O_1‒3 and water molecules is fewer and their average bond length greater than in Ca²⁺-containing foams, indicating enhanced hydrogen bonding strength in Ca²⁺-based systems at high water hardness. These results deepen our microscopic understanding of how mine water hardness influences foam stability, elucidating microstructural changes and interactions among surfactant molecules and water within foam liquid films.