Abstract: To address the problem of high fine-particle content and difficult dewatering in coal preparation products, taking the flotation clean coal from Xinwen Xiezhuang Coal Preparation Plant in Shandong Province as the research object. Experimental and simulation methods were employed to investigate the effects and mechanisms of the anionic surfactant sodium dodecyl sulfonate (SDSA) and the cationic surfactant dodecyltrimethylammonium chloride (DTAC) on the filtration dewatering of clean coal. The experimental results showed that, without the addition of reagents, the moisture content of the filter cake was 36.84%. After the addition of both reagents, the filtration dewatering of clean coal was effectively promoted, and the filtration rate was improved. The optimal dosage of SDSA was 200 g/t, at which the moisture content of the filter cake was 27.79%, while the optimal dosage of DTAC was 800 g/t, with a corresponding filter cake moisture content of 28.92%. At low dosages, SDSA exhibited an excellent promoting effect on the dewatering process. The contact angle results indicated that the adsorption of both surfactants enhanced the hydrophobicity of the coal surface. At low concentrations, the contact angle of the coal sample treated with SDSA was greater than that of the sample treated with DTAC, and the maximum contact angle of the SDSA-treated coal sample reached 79.61°. The XPS and FTIR results showed that, after the action of both reagents, the oxygen content in the coal decreased, and the amount of oxygen-containing functional groups was reduced. Both reagents effectively enhanced the hydrophobicity of the coal samples. The simulation results indicated that the adsorption of SDSA on the coal surface was more uniform than that of DTAC and could penetrate deeper into the internal structure of the coal. After adsorption, the mean square displacement of water molecules on the coal surface was relatively large, reaching 5.31 × 10⁻²¹ m²/s, suggesting that SDSA adsorption had a stronger enhancing effect on the hydrophobicity of coal. The research results can provide a theoretical basis for reducing the moisture content of clean coal and improving dewatering efficiency in coal preparation plants.