Urban underground space (UUS) use is indispensable to urbanization, thereby deserving a delicate disposal as a critical component of urban land administration. Considered an important instrument for modern land administration, however, the existing underground land value appraisal and land pricing approaches lack deliberations in the external socio-environmental effects of underground land development, thus are likely to fail to guarantee urban sustainability. With the objective of addressing such deficiencies, this paper expands the understanding of underground space into the scope of resource assets, presents some deeper reflections on underground land value and land pricing from the urban sustainability perspective, and ultimately sets up a sustainability oriented underground land pricing mechanism that incorporates external benefits, external costs and business revenues. Based on the authors’ previous works on the visualization and spatial analysis of socio-environmental externalities of UUS uses, a GIS aided case study is employed to illustrate the applicability of the proposed underground land pricing mechanism. It is hoped that the findings of this study will assist underground land administration in improving the stakeholders’ perceptions toward the value of underground land and in facilitating more reasonable underground land governing policies and pricing instruments in favor of urban sustainability.