Abstract: There are tremendous reserves of low rank coal resources in China,and the efficient utilization of coal resources can ensure the energy security. High value coal gas,tar and char can be obtained from low rank coal by pyrolysis technology,which achieveshigh value cascade utilization. In this paper,the pyrolysis mechanism of low rank coal was elucidated through three stages of pyrolysis process. In addition,the effects of pyrolysis conditions including coal rank,temperature,particle size,heating rate and atmosphere,and pretreatment methods such as acid washing,hydrothermal treatment,swelling and ionic liquid on pyrolysis reaction of low rank coal were described in detail. Besides,the catalytic pyrolysis of low rank coal is beneficial to high-quality pyrolysis products because of the directional control in pyrolysis process. Based on the differences in catalyst characteristics and catalytic behavior,the effects of different catalysts including molecular sieves,transition metal compounds,alkali metal compounds,and natural ores on the catalytic pyrolysis of low rank coal were classified. On the basis of the research status and latest development of low-rank coal pyrolysis technology,the technology of low rank coal pyrolysis for solid heat carrier,gas heat carrier and moving bed pyrolysis of internal components were summarized,and the further research direction for low rank coal pyrolysis were prospected,so as to provide a theoretical basis for the development of low-rank coal pyrolysis technology.