Abstract:The application method of GIS technology is proposed in optimizing the earthwork of the surface and underground space development of mountain cities. GIS technology can not only directly show the connection of urban surface space with natural environment, but also realize the calculation of earthwork with the different design surfaces. Combined with the calculation of earthwork in the underground space, the amount of earthwork development in urban three-dimensional space is obtained, which guides the vertical optimization design of road network and land use. Taking Longxing RS standard zoning road network and land earthwork optimization as an example, after optimization, the good economic and social benefits for the urban development and construction are achieved.