Abstract: In this paper, the intension of underground space is introduced, and the view that underground space is the key strategic resource of urban areas is pointed out. It is suggested that the underground space development idea should be changed, and the leading role of planning is emphasized. The underground space developing experience in Beijing is introduced, an underground space planning compiling system of citysubregionspecial region is discussed and established, the territory spatial planning requirements of "ecology first, base line, special plan and rigid control" should be put into practice, and the key contents and technical methods of underground space planning compiling in various levels are proposed. It is pointed out that the underground space system should be strengthened from the aspects of establishing comprehensive control system, promoting the technical standard integration, improving legislation system and establishing 3D information platform, so as to improve the planning implementation guarantee of underground space. It is concluded that: (1) As the special planning in territory spatial planning system, underground space planning should be accompanied by underground space planning compiling system. (2) As for planning level, the regionwide and overall underground space planning of citysubregionspecial region should be established and improved step by step, and the alllevel underground space planning compiling should be promoted. (3) As for planning contents, we should ground underground space resource characteristics and environment bearing capacity, understand the ecological base line of underground space, rationally divide the ecological sections and key subregion with special development, and coordinate underground facilities layout relationships with various functions. (4) As for planning implementation, the rigid control transmission mechanism of underground space should be improved, underground space system construction should be strengthened, and the rules related to department control, technical standards, ownership control and information management should be improved, so as to guide the rational and scientific use of underground space resources.

Key words: territory spatial planning, underground space planning, planning compiling, planning implementation guarantee