A model experimental bench is built to compare the differences in thermo-mechanical (TM) behaviours of traditional energy pipe pile (TEPP) and phase-change energy pipe pile(PCEPP), and obtain the TM performance of enhanced PCEPP. The results show that the PCEPP can significantly enhance the heat transfer performance (HTP), slow down the temperature and mechanical properties variation of pile and soil. The composite enhancement has the most significant enhancement in HTP, but it has also the greatest influence on the temperature of the pile and soil and the greatest change in the mechanical characteristics of pile. A 3-D CFD model was built to explore the impact of the PCM backfill form. The findings indicate that the cylindrical backfill has the best HTP and mechanical properties of the pile body. When using radial layered backfill with PCM, the backfill with increasing phase-change temperatures(PCT) from the inside to outside can increase the long-term HTP of pile while slowing down pile temperature change and minimizing thermal impact on soil.