Abstract: Aiming at the deep-buried U-bend pipe heat exchange system,the effects of buried depth（H） and connecting pipe length（D_c） between two standpipes on the heat transfer of the buried pipes are proposed.Combined with an actual deep-buried geothermal energy building heating project,five different numerical models with different buried depth and horizontal connecting pipe length were established based on obtaining the drilling temperature,the vertical ground interpretation data of the buried pipe,and the thermal physical properties of the drilling core.Numerical calculations show that the heat transfer performance of deep-buried U-bend pipes is significantly affected by H and D_c.When H is constant and D_c continues to increase,although the heat transfer rate per meter of the buried pipe continues to increase,the increase rate gradually decreases.When D_c is constant and H continues to increase,the heat transfer rate per meter of the buried pipe continues to increase and the increase rate remains basically unchanged.