Oil shale semicoke, the product of oil refining process at oil shale retorting, possesses more ash content and lower calorific value, and now is mainly treated by piling up. But due to some phenolic compounds, sulfides and polycyclic aromatics contained in the leachates, oil shale semicoke may cause severe damage to the environment at the piling-up process, which has been a bottleneck in the further development and utilization of oil shale, while utilizing the combustion of oil shale semicoke to produce heat is an effective use way. At this foundation the article further explored the utilization possibility of the combustion of oil shale semicoke and biomass. The thermogravimetric combustion experiment of oil shale semicoke and cornstalk blends was conducted with temperature programming thermoanalysis technology, which was to investigate the change of different combustion components of Wangqing oil shale semicoke and cornstalks during the whole co-combustion process. And the X-ray diffraction experiments of Wangqing oil shale semicoke at different burnout temperatures were conducted to explore the influence of the mineral on the combustion of oil shale semicoke. The change curves of the combustion component of Wangqing oil shale semicoke and cornstalk blends were acquired by the thermogravimetric curve simulation method based on the kinetics of solid-state decomposition. The results of X-ray diffraction experiments showed that the decomposition and polymerization reaction of the mineral of Wangqing oil shale semicoke mainly occurred at 873-1 023 K. The thermogravimetric combustion experiment of oil shale semicoke showed that the combustion process of the semicoke went through 4 stages, and the stage of volatiles emission burning went through 2 stages for the semicoke with high ash content, which was different from other oil shale semicokes. The 4 main stages of the combustion of Wangqing oil shale semicoke and cornstalk blends included volatiles emission burning, fixed carbon burning, residual fixed carbon burning and carbonate minerals decomposition stage. The stage of volatiles emission burning went through 1 stage, while the stage of fixed carbon burning went through 2 stages, for the combustion of fixed carbon could not be burned out during one process. The mixed cornstalks promoted the burning of volatiles of the blends and made the decomposition of carbonate minerals migrate to low temperature area. The free energy of activation and the reaction order of the main co-combustion process of the blends were calculated. The results showed that the free energy of activation needed at different co-combustion stages of the blends had distinct limitation, and the free energy of activation at the stage of volatiles emission burning was about 181, 227-233 kJ/mol at the stage of fixed carbon burning, 256-262 kJ/mol at the stage of residual fixed carbon burning, and 288-293 kJ/mol at the stage of carbonate minerals decomposition. The free energy of activation of the blends combustion decreased due to the mixed cornstalk, which also promoted the combustion reaction, and the change of the reaction order could be as the characterization of the combustion component changing in different stages. The study results can provide theoretical technical support for the industrial utilization of the combustion of oil shale semicoke. [ABSTRACT FROM AUTHOR]