Abstract: A simulation experimental study on the generation of hydrogen sulfide(H₂S) by using the high pressure reactor within a closed system has been conducted and reported earlier,but the H₂S generated is very little,or too little to be detected.A novel quartz tube simulation method is thus developed to simulate the generation of H₂S with an open system.Some chemical reagents,such as hexane,calcium sulfate,sulfur and pyrite,are used to investigate the generation of H₂S in the simulation experiment;and a kind of low mature marlstone is also used to simulate the generation of H₂S during the generation of hydrocarbon.The results show that calcium sulfate may react with hexane under high temperatures but not easily,and the H₂S amount generated is little;the elemental sulfur can react easily with hexane under relatively low temperatures,generating large amounts of H₂S;pyrite can also react with hexane and generate large amounts of H₂S,mainly due to the reaction of the elemental sulfur released under high temperatures with hydrocarbons.The low mature marlstone can generate large amounts of H₂S during the hydrocarbon generation simulation,because of its high content of pyrite.The successful simulation of the generation of H₂S provides an important experimental basis for the study on the genetic mechanism of H₂S.