Abstract: To determine the influence of groundwater flow on the temperature field and heat transfer characteristics of the large-scale,multi-branch pipe cluster ground source heat pump system,a three-dimensional heat transfer-seepage coupling model considering groundwater flow and geological stratification is established based on the 880 buried pipes site of Shanghai Astronomy Museum. The model is verified through thermal response tests. The results show that groundwater flow causes temperature interference along the groundwater flow direction within the pipe clusters and between branch clusters,and the temperature interference phenomenon is relatively pronounced in the depth of 89.5-120.3 m. Groundwater flow promotes the total heat transfer of the pipe cluster and reduces the heat transfer difference between summer and winter operating conditions. The percentage increase in heat transfer is proportional to the hydraulic gradient and follows a logarithmic function. When the hydraulic gradient is greater than 0.005,the percentage increase in heat transfer tends to stabilize.