With high content of oxygen and high thermal reactivity,lignite is an important feedstock for the preparation of high value-added chemicals,such as phenols and humic acids. The heteroatoms especially the abundant oxygen-containing functional groups（e.g. phenolic hydroxyl groups and carboxyl groups)result in the existence of a large number of hydrogen bonds in lignite. Hydrogen bonds are usually involved in thermal conversion（pyrolysis,drying and direct liquefaction)of lignite,mainly including hydrogen bonds in lignite and hydrogen bond between lignite and solvents. Those two kinds of hydrogen bonds apparently differ in geometry configuration and strength. To present,various hydrogen bonds can be figured out by experimental methods（such as volumetric swelling degree and infrared spectroscopy),as well as quantum chemistry calculations. Hydrogen bonds in coal and hydrogen bonds between lignite and solvent exist widely,and significantly affect thermal conversion of lignite,especially pyrolysis and direct coal liquefaction. Hydrogen bonds in lignite play important roles in the stabilization of macromolecular network of coal,which can promote dehydration of phenolic hydroxyl groups and carboxyl groups,as well as the low-temperature crosslinking reactions during thermal conversion and is not conducive to the formation of light products such as tar. The hydrogen bond between lignite and solvent is an important form of interaction between lignite and solvent. Its strength significantly affects the physical and chemical reactions of lignite in the process of thermal conversion,such as extraction,swelling and deoxidation. It is of great significance for the clean and efficient conversion of lignite to fully understand the existing forms and influencing factors of hydrogen bonds related to lignite,and to regulate the hydrogen bonds on this basis. To present,the main purpose of hydrogen bonds modulation is destroying hydrogen bonds which exist in lignite,so that the crosslinking reactions during thermal conversion can be suppressed to some degree. It can be realized by preheating treatment at relatively low temperature,as well as solvent pretreatment using stronger hydrogen bonds acceptors such as pyridine and ionic liquid. However,current study about hydrogen bonds formed by lignite and solvents are mainly qualitative researched,the in-situ observation and quantitative analysis of the lignite thermal conversion are lack.