Abstract: In order to study the combustion characteristics of pellet fuel prepared by blending wheat residue and waste liquid in pulping process, the combustion thermodynamics and kinetics characteristics were analyzed by thermogravimetric test. The results showed that pulping waste liquid resulted in the secondary combustion stage of fixed carbon in the pellet fuel. The addition of pulping waste liquid was helpful to decrease the volatile content of pellet fuel, the ignition temperature, and maximum combustion rate temperature in the fixed carbon combustion stages, which had a positive synergistic effect on the combustion of pellet fuel. The thermogravimetric data were fitted with a first-order dynamics equation, and the correlation indexes of the prepared pellet fuel were all above 0.95. The addition of the pulping waste liquid reduced the activation energy and frequency factors of the pellet fuel in the volatile combustion and fixed carbon combustion stages, respectively. The activation energies of the corresponding stage when a solid mass fraction of 53% of the waste liquid were 72.85 and 83.52 kJ/mol, and the frequency factors were 2.82×10⁶ and 3.73×10⁵ min^-1, respectively. The addition of the pulping waste liquid made the pellet fuel easier to burn, and the combustion process became stable and uneasy to deflagrate.