Abstract: The remaining coal pillar groups in the residual mining area are widely distributed,with considerable re⁃serves.Most of them are scarce and high⁃quality resources,which have good mining value and potential.Long⁃term re⁃tention of remaining coal resources in residual mining areas is very easy to ignite naturally,polluting the environment,endangering health and aggravating carbon emissions.Due to the internal characteristics and external environmental impact,chain instability may occur in the residual mining area,which may lead to multiple disasters such as overbur⁃den collapse,surface subsidence,dynamic ore pressure,gas gushing,water and sand inrush(pea/coal slime)or fire area expansion,and threaten safe⁃green mining.The mining of remaining coal resources will also form a large volume of mining space,which is also a potential developable“resource”for CO 2,hydrogen,oil and water storage.The main technical challenges faced by the mining remaining coal pillar groups include:how to accurately explore the oc⁃currence status,how to deal with the nearby water in advance,how to effectively prevent and control natural fire,how to fully dispose of the surrounding gas,how to scientifically select the mining method,and how to control the surrounding rock.The mining of remaining coal pillar groups involves the“active development of backfilling”and “passive transformation of grouting”for underground developing,and the technical challenges are as follows:where is the key backfilling/grouting location,what is the key backfilling/grouting material,the optimization of technical pa⁃rameters of key backfilling/grouting,and the stable operation and maintenance of the key backfilling/grouting under⁃ground space.The above research is expected to provide scientific guidance and decision⁃making basis for the green mining of remaining coal pillar resource and the efficient development of space resources in the residual mining area.It is necessary to strictly abide by the“Coal Mine Safety Regulations”,the technical specifications and require⁃ments formulated by local governments at all levels.The precision exploration,water treatment,fire prevention and con⁃trol,gas disposal,method selection,surrounding rock control and other hidden danger management should be compre⁃hensively considered.And the“safety demonstration⁃scheme design⁃theoretical breakthrough⁃technical research⁃equip⁃ment development”should be carried out in mining the remaining coal pillar resources and developing the underground space according.It is strived to achieve a breakthrough in the basic theory and key technology of green mining of remaining coal resources and underground space development in residual mining areas,and help the high⁃quality development of China’s coal industry.