Ecological space is the natural foundation of urban sustainable development, and its composition, scale, and distribution have an important impact on the ecological security of the territorial space. The territorial spatial planning and urban planning and construction management must incorporate the concept that mountains, rivers, forests, fields, lakes, and grasslands are a community of life, optimize the pattern of territorial spatial development and protection, and reasonably protect and utilize ecological space. Taking Nanning City as an example, based on a thorough review of the concepts of controlling territorial space use, this paper proposes an ecological spatial control system with ecological control line as its core. By the evaluation of ecological security and sensitivity, we identify key ecological problems and core ecological resources in the study area, construct a regional ecological security pattern, draw an ecological control line, formulate a spatial control scheme. We thus establish a method of ecological spatial planning based on background evaluation, pattern construction, and control of the bottom line. The results show that:(1) The overall ecological security of the study area is relatively good,but the occupation of ecological space by construction lands needs to be solved.(2) The study area is of 40.70% highly sensitive ecological area, all of which are spatially contiguous and concentrated with highly ecological connectivity, and all of which are the main carriers of the ecological security pattern and ecological control line. (3) The ecological security pattern of the study area consists of one axis, one ring, five zones, multiple corridors, and multiple nodes. (3) The ecological control line accounts for 86.03% of the total area, and through the implementation of hierarchical control, the core ecological resources are strictly protected and the secondary ecological resources are reasonably utilized. (4) The ecological control line, which controls the ecological space in the whole area, is the premise and foundation of the territorial spatial planning as well as urban planning and construction management. The results of this work can provide technical and decision-making support for the territorial spatial planning and ecological protection and restoration in Nanning and reference for ecological spatial planning in other cities.