Abstract: Tar-rich coal is a kind of bituminous coal with medium and low rank metamorphic degree on coal-rank, with high hydrogen-rich structure content and high tar yield. To explore the advantages of oil production from tar-rich coal, it is necessary to study the structural characteristics of tar-rich coal to clarify the correlation mechanism of hydrogen-rich structure for the tar reaction mechanism of tar-rich coal pyrolysis. Shaanxi tar-rich coal was selected as the main research object, and Inner Mongolia lignite and Ningxia anthracite were selected as the research objects of reference comparison. The physical and chemical characterisation was carried out by elemental analysis, ¹³C-NMR, FTIR and XPS, and the macromolecular structure models of different coal ranks were established and optimized. The product distribution and pyrolysis characteristics of tar-rich pyrolysis process were calculated by ReaxFF MD, and the pyrolysis process and product distribution were analyzed in detail. The results show that when the pyrolysis temperature is lower (≤3500 K), the tar yield of tar-rich coal pyrolysis is higher, and the yield of heavy tar in tar products is higher. The volatile products of Inner Mongolia lignite can reach about 80% at most, of which the gas yield accounts for 40%–60% of the volatile products, and the proportion of light tar in the tar component can reach 60%; the volatile products in tar-rich coal can reach up to about 60%, of which the highest proportion is the heavy tar component, which accounts for 50%–60% of the volatile products. The total yield of volatile matter in the pyrolysis products of Ningxia anthracite is low, and the highest is not more than 30%. Compared with medium and low-rank coal, it has a greater disadvantage in pyrolysis oil and gas products. Due to the fracture of the aliphatic bridge bond（hydrogen-rich structure）between the aromatic rings in the tar-rich coal, the free radical fragments of the tar-rich coal molecules during the pyrolysis process retained a relatively large carbon skeleton structure（C₁₄–C₅₀）. Through the simulation of molecular structure characterisation analysis and pyrolysis experiments of coal with different coal ranks, it is found that fat side chains and bridge bonds are the key structure for pyrolysis to generate volatile products. The fracture of fat side chains has a great contribution to the generation of gas products and light tar, and the size of molecular fragments caused by the fracture of bridge bonds determines the proportion of heavy tar and light tar in tar products. When the pyrolysis temperature is high, the secondary reaction of coal pyrolysis oil and gas products is intensified, decreasing tar yield.