Abstract: Facility agriculture applications are often required for the seasonal match between the solar energy supply and heating demand. However, the heating demand is also intensive and highly seasonal in the severely cold areas. The solar energy resources have restricted the large-scale application of the solar heating systems, due to the strong temporal variability. In this study, an efficient solar heating system was developed with the seasonal thermal energy storage. The efficiency of the energy utilization was also improved to avoid the dependence on the fossil fuels in facility agriculture. A systematic investigation was then implemented on the energy performance, the technical and environmental feasibility of a solar heating system with the seasonal thermal energy storage. A practical solar district heating system was operated in Lanzhou City of western China. Experimental and simulation analysis analyses were combined for an engineering-oriented heating in cold regions. A solar collector subsystem consisted of a large-capacity seasonal thermal energy storage unit, a water-source heat pump unit, and a terminal greenhouse heating subsystem. A dynamic simulation model was established to describe the transient thermal behavior and energy interactions among different subsystems. Operational data was validated with the maximum errors of less than 9.2% for the outlet water temperature at the collector field and 4.1% for the water temperature in the seasonal thermal energy storage, indicating the high accuracy and reliability for the long-term performance. The performance showed that the annual collected heat of the solar collector subsystem reached 436.5 MW·h under an annual total solar irradiation of 1,096.8 MW·h, with an average collector efficiency of 39.8%, indicating the stable solar energy harvesting under cold-climate conditions. The annual heat release was 384.8 MW·h from the seasonal thermal energy storage. A heat release efficiency was achieved as high as 90.0%, fully meeting the high effectiveness of the seasonal thermal energy storage to reduce the heat loss for the inter-seasonal energy transfer. The seasonal thermal energy storage and the water-source heat pump were combined with an average COP of 3.98. A solar fraction of 82.4% was significantly improved the utilization efficiency of the solar energy for the reliable heat supply in agricultural greenhouses during the heating season. Annual performance analysis further indicated that the system performed well under severely cold conditions, with a thermal energy storage efficiency of 83.0% and the stable long-term operation. In terms of the environmental benefits, there were was a primary energy savings rate of 70.2% and a CO₂ reduction rate of 143.9%, compared with the conventional coal-fired boilers. The significant decrease was observed in the emissions of SO₂, particulate matter, and NO_x. The solar heating system with the seasonal thermal energy storage shared the high applicability, operational reliability, and promotion potential in the facility agriculture. The finding can also provide a solid theoretical basis for the large-scale application under the urban and agricultural heating scenarios in Northwest China.