Abstract: To study the influence of long-term operation of ground source heat pump (GSHP) on geothermal field in heat transfer area of hot-summer and cold-winter regions, taking a GSHP project in Nanchang City as an example, this paper analyzes the variation characteristics of geothermal field and heat-cold accumulation inside and outside the heat transfer area of the demonstration project over four years of operation. The project arranges seven temperature monitoring holes in the center and surrounding areas of the GSHP group for comprehensive monitoring of geothermal field changes in heat transfer area during the four-year operation. The analysis results show that the geothermal temperature inside and outside the heat transfer area changes periodically with the four-year operation of GSHP; The geothermal temperature increases with increasing depth vertically, and the variation range decreases gradually; Radially, geothermal temperature variations around the heat transfer area gradually decreases with increasing distance from hole group; The thermal influence radius of the hole group is 3-6 m during the four-year operation; The average temperature at the hole group boundary increases merely by 0.13 ℃, indicating insignificant heat accumulation after the four-year operation. These findings provide references for the site design of GSHP heat transfer holes.