Abstract：The oil shale thermal cracking CT images under different temperatures are considered as the analytical objects；and the basic theories of fractals to the thermal cracking procedure of oil shale are applied for the first time. The distribution laws of the thermal fissures within the range of 200 ℃–600 ℃ of oil shale square body of 7.0 mm in length are researched；and the fractals dimensions and initial distribution values of the fissures under different temperatures are obtained. The achieved results show that the thermal fissures have strong self-similarity according with fractals laws，and the values of fractal dimensions are ranged from 1.0 to 1.5. The relationship between fractals dimensions，initial distribution values and temperatures is established. With fractals theory，the thermal cracking procedure of the oil shale，distribution state and complexity of the fissures are analyzed. The derived conclusions for analyzing the evolution of micro-seepage channels in the oil shale pyrolysis have important references；and at the same time，a new method and certain ideas for thermal cracking procedure of other rocks with fractals theory are offered.
