Abstract: Elemental distribution, compositional variation, microstructural feature, surface pore structure, pyrolysis characteristic and reactivity of samples derived from inert/oxidative torrefaction performed in 493–573 K were investigated. The results illustrated that reaction temperature was the dominant factor affecting fuel quality of torrefied sample, and the addition of oxidizing agents would strengthen the variations in fuel properties after undergoing torrefaction. Increasing reaction temperature would promote the decomposition of oxygen containing functional groups from the particles, when torrefaction performed in raw flue gas atmosphere at 573 K, the H/C and O/C reached the minimum values (0.188 and 0.259). Additional oxidizing agents would synergistically modify the surface functionality distribution, microstructure and surface physical structure of rice husk particles, and the increase of temperature was beneficial to this phenomenon. The critical values were obtained from the sample torrefied in raw flue gas atmosphere at 573 K, the minimum I_{(Gr + VL + Vr)}/I_D value was 1.79 and the maximum specific surface area was 295.78 m²/g. By means of the utilization of Coats-Redfern approximation function, the pyrolysis kinetics (14.84 → 28.82 kJ/mol) and characteristic parameters would be determined via the TGA data for each sample. Flue gas seemed to be more energy-saving and efficient for improving fuel quality and storage stability of biomass.