The dewatering kinetics and mechanism were investigated of lignite samples from Inner Mongolia, China, and of dewatered samples moisturised at a relative humidity of 75% at 303 K for 48 h. Dewatering was conducted in nitrogen at temperatures in the range 333-433 K, and the physical structural changes before and after drying were investigated. The results indicated that the drying process could be divided into four stages, an increasing rate stage, constant rate stage, relatively rapid decreasing rate stage and relatively slow decreasing rate stage. The relatively rapid decreasing rate stage and relatively slow decreasing rate stage could be described in terms of the Jander model and the first-order kinetics model, respectively, and the corresponding dewatering mechanism equations were derived. The effective diffusion coefficients and diffusion activation energy were calculated using Fick’s second law. The diffusion activation energies for the relatively rapid and slow decreasing rate stages were 35.80 and 40.75 kJ/mol for the raw coal and 27.80 and 37.34 kJ/mol for the moisturised coal, respectively. The effective diffusion coefficient was significantly affected by the drying temperature due to pore structure changes, when other drying parameters were fixed. The results show that the mechanisms involved in the relatively rapid and slow decreasing rate stages are three-dimensional diffusion and nucleation and growth, respectively, and that different forms of water are involved in the two stages., The dewatering kinetics and mechanism were investigated of lignite samples from Inner Mongolia, China, and of dewatered samples moisturised at a relative humidity of 75% at 303 K for 48 h. Dewatering was conducted in nitrogen at temperatures in the range 333-433 K, and the physical structural changes before and after drying were investigated. The results indicated that the drying process could be divided into four stages, an increasing rate stage, constant rate stage, relatively rapid decreasing rate stage and relatively slow decreasing rate stage. The relatively rapid decreasing rate stage and relatively slow decreasing rate stage could be described in terms of the Jander model and the first-order kinetics model, respectively, and the corresponding dewatering mechanism equations were derived. The effective diffusion coefficients and diffusion activation energy were calculated using Fick’s second law. The diffusion activation energies for the relatively rapid and slow decreasing rate stages were 35.80 and 40.75 kJ/mol for the raw coal and 27.80 and 37.34 kJ/mol for the moisturised coal, respectively. The effective diffusion coefficient was significantly affected by the drying temperature due to pore structure changes, when other drying parameters were fixed. The results show that the mechanisms involved in the relatively rapid and slow decreasing rate stages are three-dimensional diffusion and nucleation and growth, respectively, and that different forms of water are involved in the two stages.