Abstract: In order to investigate the dynamic dewatering features of the lignite under the different particle size, medium and temperature, taking the flue gas with o xygen content about 10. 5% as the dewatering medium, the fluidized bed dewatering device system was applied to the dewatering experiments of the lignite from the ea st part of Inner Mongolia.The results showed the fluidized bed dewatering process of the lignite was divided into a constant rate dewatering stage and a down speed rat e dewatering stage.The average dewatering rate was increased with the dewatering temperature increased.When the dewatering temperature was over 220。C, only 5 minutes passed and the dewatering rate could reach the inflexion dry base moisture content (5%) of the coal sample.Under the dewatering temperature of 260 °C, the a verage dewatering rate would be 4.33 kg/min.Finally the Fourier transform infrared spectrometer was applied to analyze the structure variation of the fluidized bed dewa tering coal samples.It was found the oxygen functional groups in the coal samples after dewatering was reduced highly, the absorption strength was only 51.03% of the raw coal and the main structure of the coal sample was no change.