In order to discover the incineration characteristics bagasse pith and low-quality soda black liquor solids were studied in thermogravimetric analyzer under dry air from ambient temperature to 800 degrees C, to obtain thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG) analysis curves. The experimental results show that the combustion process is not a summing up calculation, but has clearly synergistic effects. Bagasse pith generally affects the devolatization of volatile materials in the combustion. It is inhibited in the beginning and accelerated in the middle and afterward periods. Due to the increment of bagasse-pith's proportion in the mixture, it is found that temperature difference of the volatile materials' devolatization rise, volatile materials evolve out quickly, and both the rate and speed of mass loss enhance. Kinetic analysis indicates that parameters E and A of Arrhenius equation during the volatile matter degradation are found to be exponentially fitted well in the combustion process.