Abstract: Coal dust poses a significant threat to the occupational safety and health of miners. The low surface energy of coal makes it difficult for coal dust to be wetted by water. Surfactants are usually added to water to improve the wetting effect of coal dust. However, the use of surfactants may result in increased costs, water pollution, and disruption of local ecological balance. Micro-nano bubble water has the characteristics of low surface tension. However, the wetting characteristics of micro-nano bubble water on coal and its moistening mechanism are not clear, which limits the industrial application of micro-nano bubble water. Based on this, this paper studied the wetting characteristics of micro-nano bubble water on coal, and reveals the moistening mechanism of micro-nano bubble water on coal. The results showed that the scattered light intensity, dissolved oxygen content and zeta potential of micro-nano bubble water increased first and then decreased with the circulation preparation time of micro-nano bubble water, and reached the maximum value at 15 min. If the preparation time was too long, bubbles would merge with each other. Based on the results of proximate analysis, ultimate analysis, nuclear magnetic resonance spectroscopy (¹³C-NMR) analysis, Fourier transform infrared spectroscopy (FTIR) analysis and X-ray photoelectron spectroscopy (XPS) analysis of coal before and after micro-nano bubble water treatment, the molecular structure models of coal before and after micro-nano bubble water infiltration were established. The molecular formulas were C₁₀₆H₆₄N₂O₅ and C₁₀₅H₇₀N₂O₆, respectively, and the bridge carbon ratio was 0.48, which was consistent with the bridge carbon ratio of 0.475 and 0.476 calculated by ¹³C-NMR spectra before and after micro-nano bubble water treatment. The coal molecules after micro-nano bubble water treatment contain carboxyl groups, which was consistent with the results of FTIR and XPS analysis. For the coal and water micro-wetting system after micro-nano bubble water treatment, the relative concentration of water molecules below the coal and water interface was large, and the relative concentration peak of water molecules above the coal and water interface was small. The degree of aggregation of water molecules was high, the degree of dispersion was small, the interaction energy between coal and water was large, and the contact angle of coal and water was small. Micro-nano bubble water could improve the wetting effect on coal. With the increase of wetting time, the contact angle between coal and water decreased, and the width of the contact surface increased gradually. The research results laid a theoretical foundation for the use of micro-nano bubble water for coal dust control.