Abstract: Using supercritical water and superheated steam to pyrolyze coal in situ and convert solid coal into combustible gas is an important technical means of coal fluidization mining.In this paper, a newly developed high-temperature and high-pressure reactor was used to carry out a pyrolysis test of lump bituminous coal, and the influence mechanism of supercritical water and superheated steam on coal pyrolysis was explored,Analysis of the influence of supercritical water and superheated steam temperature and pressure on coal pyrolysis products and pyrolysis rate.The study showed that: compared with 400℃, the gas production at 700℃ under 24Mpa increased by about 43 times, the hydrogen content in the precipitated gas increased by 29%, the methane content decreased by 7%, the carbon monoxide and carbon dioxide contents decreased by 10% and 12% respectively, and the weight