In order to explore the efficient heat transfer characteristics of medium-deep coaxial buried pipe heat exchangers, a heat transfer model was constructed between the medium-deep coaxial buried pipe heat exchanger and surrounding rock and soil based on the fluid flow heat transfer equation. COMSOL software was used for numerical analysis and calculation of heat transfer, and the nominal heat transfer of the model was studied under different burial depths, inner pipe thermal conductivity, circulating water flow rate, and cementing material thermal conductivity conditions. The research results indicate that the thermal conductivity of the inner pipe, the flow rate of circulating water, and the thermal conductivity of the cementing material have a significant impact on the nominal heat extraction. The thermal conductivity of the inner tube decreases from 0.5 W/(m·K) to 0.002 W/(m·K), with a nominal increase in nominal heat extraction of 289.4%. The circulating water flow rate from 20 m²/h rises to 45 m²/h, with a nominal increase in nominal heat extraction of 124%. The thermal conductivity of cementing materials increases from 0.8 W/(m·K) to 1.8 W/(m·K), with a nominal increase in heat extraction of 2%. Finally, relying on a Pilot Demonstration Project of Medium and Deep Geothermal Energy for Building Heating at CCTEG Xi'an Research Institute (Group) Co., Ltd., differential analysis was conducted on experimental and simulation data under continuous operation for 168 h of the project. The research results have certain guiding significance for the optimization design of medium-deep coaxial buried pipe heat exchangers and the efficient development and utilization of medium-deep geothermal wells.