Abstract: In order to seek the suitability of the coal underground gasification technology to lean coal, the gasification features of the lean coal seam was studied 0 n the underground seam model experiment platform.The results showed that the calorific value of the coal gas from the lean coal seam under the air gasification conditi on would be 3 404 MJ/m3 and would be better than the calorific value of coal gas from the underground lignite seam under the air gasification.Under the rich oxygen an d steam gasification of the lean seam, the effective components and calorific value of the coal gas would be increased with the oxygen concentration in the gasification agent increased and the coal gas produced with the oxygen volume fraction of 40%%0% would be suitable for the gas-fired power generation. The pollutant analysis sho wed that the partial pollutant content of the coal gas cooling water would be over the limits.The analysis on 3D shape of cavity and coal seam roof, the cavity would be steadily forward along with the coal gasification channel and the lateral expansion width would be reduced from the ignition location of 0.86 m to the terminal location of 0.43 m.The overburden subsidence depth above the simulated seam would be 6.5% of the total thickness and the subsidence area would be about 6.1% of the total surf ace area.