Abstract: THF test method in the hydrate research is used to conduct online monitoring of temperature drop and hydrate formation process of tetrahydrofuran aqueous solution system by RC1e calorimetry reaction system and ReactIR online analysis system and study the changes of temperature, heat and internal composition in the formation of hydrate solution system. Experimental results show that 19 % tetrahydrofuran aqueous solution system forms hydrate crystal nucleus at －4 ℃ and releases a large amount of heat due to the phase change, causing temperature rise of the solution system. In the formation of hydrate crystal nucleus, under the induction of tetrahydrofuran, more water molecules are subject to interaction by hydrogen bonds to form the basis of hydrate structure. Solution system heat and infrared change results describe the process and action mechanism of hydrate formation in the tetrahydrofuran solution on a certain level, which can providea theoretical basis to the future prevention of hydrate plugging in the natural gas pipeline.