<p>In the long-term application of medium-to-deep ground-source heat pump (GSHP) heating systems in northern regions, issues such as soil thermal imbalance, declining heating efficiency, and high operational energy consumption are widespread. In existing studies that conduct optimization analyses in conjunction with peak-off-peak electricity pricing mechanisms, most researchers have not fully accounted for the structural and temporal differences in peak-off-peak pricing policies across different regions. This study takes a typical residential community in Handan City, Hebei Province, as its research subject. Using the TRNSYS platform, a dynamic simulation model of a photovoltaic/solar thermal coupled medium-to-deep ground-source heat pump heating system (PV/T-GSHP) based on peak-off-peak electricity pricing was developed. Furthermore, four typical cities belonging to different climate zones—severe cold, cold, hot in summer and cold in winter, and hot in summer and warm in winter—were selected. A multi-objective comprehensive evaluation index system was established based on resource conditions, energy benefits, environmental benefits, and economic benefits. Key indicators such as the system’s primary energy utilization rate, heating capacity, CO₂ emissions, and total operating costs were calculated and analyzed, ultimately leading to conclusions regarding the suitability of the PV/T-GSHP heating system in different regions. The results indicate that Guangzhou has the lowest winter heating load and exhibits a “heat accumulation” phenomenon, making it unsuitable for year-round heating using a ground-source heat pump system; Urumqi, Handan, and Nanjing achieved the highest annual CO₂ emission reduction rates of 74.70%, 74.99%, and 72.55%, respectively, with operating costs reduced by up to 92.2%, 84.19%, and 80.35% compared to conventional heating systems. Overall, the system demonstrates the best energy savings and environmental benefits in Handan, while it delivers outstanding economic benefits in Urumqi.</p>