Two typical types of Chinese lignite samples were employed to investigate the coal drying characteristics of an innovative COMBDry lignite drying system. The drying rate increased significantly with an increase in drying temperature and ratio of the flue gas, to the lignite. Using a nitrogen adsorption instrument, it was found that the drying process promoted generation and enlargement of the surface pore structures of the particles, which can enhance coal combustion rate. A horizontally fixed bed furnace and a SIGNAL S4i pulsar NDIR (infrared (IR)) gas analyzers were used to investigate the combustion characteristics of coal samples after the drying treatment. In an attempt to analyze the variation in the sample surface chemical structure during the drying process, Fourier transform infrared (FT-IR) spectrometry and Raman spectroscopy were employed for the investigation. The results showed that the concentration of aliphatic hydrogen decreased with an increase in drying temperature and resulted from the decomposition of oxygen-containing complexes (released CO and CO2) and reaction with hydroxyl groups. The number of functional groups decreased when the drying temperature exceeded 210 degrees C. The amount of carbonyl and carboxylic esters initially increased and then (210 degrees C) decreased with an increase in flue gas temperature, and the content of aromatic carbon was unchanged with the treatment. The ordered crystalline carbon changed into the crystal defect structure and amorphous carbon and the degree of graphitization decreased and thus the combustion reactivity of the dried lignite was improved.