The kinetics and thermal characteristics of oil shale semi-coke and sawdust, including their blends, during co-combustion were investigated using a non-isothermal thermogravimetric analyzer (TGA). The ratio of semicoke to sawdust in the blends by mass was set as 10: 0, 9: 1, 8: 2, 7: 3, 6: 4, 5: 5 and 0: 10. The combustion performance of samples improved significantly with increasing sawdust proportion in the mixture and rising heating rate. The kinetic analysis demonstrated that the distributed activation energy model (DAEM) could well describe the value of apparent activation energy at different fixed conversion values. Gaseous emission analysis by using the coupled Fourier transform infrared spectroscopy (FTIR) demonstrated that organic compounds were produced by the pyrolysis of sawdust, while inorganic compounds were generated during the whole combustion process. Most of the inorganic compounds were CO2 and CO. Seldom SO2 and NOx were released at the initial stage. The results obtained indicated that the blends may improve the combustion performance of oil shale semi-coke and sawdust.