Abstract: In the context of China's carbon neutrality strategy, formulating a low-carbon development strategy that adapt to the territorial space functions is of great significance to realizing green development in Chinese counties. The study took Yulong County, a rocky desertification mountainous area in northwest Yunnan, as the study area. he carbon emission coefficient, life cycle, and net ecosystem productivity estimation methods to calculate the carbon source/sink of the territorial space and analyze spatiotemporal characteristics; by analyzing the carbon source/ sink benefits, the carbon imbalance space and constructed at grid scale. Results: (1) From 2010 to 2020, Yulong County was dominated by ecological space, and living space expanded rapidly. (2) The carbon source and sink of the production-living-ecological space increased. The carbon source increased dramatically, showing the spatial distribution characteristics of "High in the west and low in the east" and high values concentrated in the southeast. (3) From 2010 to 2020, the carbon source/sink efficiency dramatically improved, and there were  obvious spatial difference; the carbon imbalance space accounted for 47.30%, with the carbon source imbalance dominating. (4) Carbon imbalance at grid scale was divided into five zones: ecological carbon sink functional zone, low-carbon priority development zone, ecological carbon sink enhancement zone, production high-carbon optimization zone, and living high-carbon control zonedifferentiated countermeasures for collaborative emission reduction within the county.  At grid scale, the territorial space in northwest Yunnan dominated by ecological space in the past ten years,  the expansion of living space accelerated. Carbon source and sink in production-living-ecological space increased, but sources were much greater than sink; the growth of carbon emissions in industrial and mining production space and living space far exceeded the carbon absorption in ecological space; the carbon source and sink efficiency was on the rise and was higher in the east and west and lower in the southeast. The carbon imbalance space accounted for 47.30%; based on low-carbon development, emission reduction, and sink increaseive carbon imbalance comprehensive zones were divided, and low-carbon development countermeasures were proposed to provide a reference for China's county low-carbon territorial space planning.