In this research, thermal analysis and combustion characteristics of mixtures of oil shale and its semicoke were investigated by means of an on-line TG-FTIR interconnection analyzer, with the aim of comparing the behavior of the mixture with that of its components. Experiments were conducted at three heating rates 20, 50 and 80 K/min in the temperature range 30-850 degrees C. Mainly three different reaction regions were observed at combustion of most of the samples studied. It was observed that ignition temperature decreases with an increase in the share of oil shale in the blend resulting in a higher yield of volatile compounds. Higher heating rates were accompanied by higher reaction temperatures and heat of reactions. Distinguishing peaks shifted to higher temperatures with an increase in heating rate. A Fourier Transform Infrared Radiation analyser (FTIR) was used to analyze combustion products during experiments. Kinetic parameters of the combustion reaction of mixtures were calculated by binary linear regression. Throughout the analysis of kinetics of the combustion experiments, it was observed that activation energies of combustion in the high-temperature region (124.2-421.7 KJ/mol) were generally higher than those of low-temperature region (67.2-48.9 Kj/mol), and this could be explained by the difference in the combustion reaction mechanism at different temperatures. The results may provide theoretical basis for further effective and economical exploitation of oil shale.