The main purpose in this study was to understand the interactions of coal particles with three amphiphilic humic acid-based polymers, which were designed and synthesized through the copolymerization of humic acid (HA) with maleic anhydride-polyethylene glycol 400 monoester, methacrylatoethyl trimethyl ammonium chloride or both of them, respectively, abbreviated as HAM, HAD and HMD. The adsorption quantities of HMD and HAD increased monotonically with the equilibrium concentration of dispersant, which were well described by Freundlich adsorption equation, but the Langmuir adsorption equation was more suitable for HAD dispersant. Besides, the we ttability of HMD solutions on the coal surface was better than others. Moreover, the HMD dispersant exhibited better viscosity-reducing and stabilizing capability for coal-water slurry (CWS) than that of HAD and HAM, which were due to the strong adsorption force that was good for improving the hydrophily and enhancing the steric hindrance and electrostatic repulsion among coal particles. (C) 2020 Elsevier B.V. All tights reserved.