为进一步了解煤炭地下气化商业化面临的关键科学问题，基于对国内外典型煤炭地下气化试验的分析，总结归纳了典型煤炭地下气化试验的区域煤层特征、气化工艺、粗煤气组分及热值等要素。结果表明，气化选址需要综合考虑降低环境风险、较好的地质条件和煤炭品位、较好的地质力学-水文地质条件等因素；钻井式煤炭地下气化已成为主流；中深层富氧气化成为重要的突破方向；气化工艺以可控式后退注入点法（Controlled Retracting Injection Point，CRIP）为主流。从埋藏深度和可燃气体组分来看，可以将煤炭地下气化分为浅层（<4 MPa）、中深层（4～18 MPa）、深层-超深层（>18 MPa）三大类。浅层煤炭地下气化主要发生水煤气反应，粗煤气中可燃气体以H2为主；中深层主要发生甲烷化反应，可燃气体以CH4为主；深层-超深层发生超临界反应，可燃气体以H2为主。将有利区评价、高效气化工艺、稳定运行控制、碳封存等四者有机结合在一起，是实现碳中和目标下煤炭地下气化商业化目标的重要途径，这将是今后煤炭地下气化技术攻关的主要发展方向。

To further understand the key scientific issues of the commercialization of underground coal gasification, based on analyzing underground coal gasification field tests  at home and abroad, this paper summarizes the characteristics and relevant elements of underground coal gasification, including regional coal seam characteristics in gasification area, gasification process, crude gas components and calorific value, and so on. The result shows that environmental risk, geological conditions, coal grade and geomechanics-hydrogeological conditions are needed to take into account in the site selection for gasification; drilling has become the main gasification mode; gasification with oxygen enriched air in medium-deep depth has become an important breakthrough direction; controlled retracting injection point is the main gasification process. In the view of gasification coal seam burial depth and combustible gas composition in the crude gas, underground coal gasification can be divided into three types: shallow layer (formation pressure less than 4 MPa), middle deep layer (formation pressure between 4 and 18 MPa), deep and ultra-deep layer (formation pressure more than 18 MPa) underground coal gasification. The chemical reaction of underground coal gasification is mainly water-gas reaction, methanation reaction and supercritical reaction in shallow layer, middle deep layer and deep and ultra-deep layer differently, corresponding to that, the main combustible gas of produced crude gas is H2, CH4 and H2. It is an important way to achieve the commercialization goal of underground coal gasification under the carbon neutral goal that organically combines together the four aspects of favorable area evaluation, efficient gasification process, stable operation control and carbon capture and storage, which will be the main technology research and development direction of underground coal gasification in the future.