Owing to the artificial backfill uncertainty, the air gap may emerge in the backfill process, which will influence the soil initial temperature distribution, and it will also influence the horizontal buried pipe heat transfer performance. The initial soil temperature numerical model with backfill air gap was set up. Using CFD software, the numerical calculation result was analyzed and compared with the theoretical calculation value without air gap and practical experimental test data. The soil initial temperature with backfill air gap in the deep of 2.2 meters presents about one degree higher than that without backfill. Then, the horizontal buried pipe coupled numerical models with the deep of 2.2 meters were established on the boundary conditions of the initial soil temperature with air gap and that without air gap. Using CFD software, the horizontal buried pipeimport/export temperature and the average heat transfer coefficient changing along with time were analyzed and compared with experimental operating data. The result shows that the soil with air gap will lead the import/export temperature rise and reduce the heat transfer performance, and the average heat transfer coefficient reduces from 2.71W/(m·℃)to 2.22 W/(m·℃).