Abstract: Based on a series of loading tests of ful-l scale model DX piles cas-t in- situ, the bearing behaviour and loadtransferring mechanism of tension DX piles are studied. The results show that the tension bearing capacity of DX pile is apparently higher than that of the pile with constant section, and the curve of load-displacement of DX pile is slowly varying. The enlarged disks bear the most of all tension bearing capacity. It is found that the unit frictional resistances of DX pile is also higher than that of the pile with constant section because of squeezed efficiency of disk. Then, the lateral resistance of tension DX pile, tension pile and compression pile with constant sections are compared. The difference of lateral resistance under tensile and compressive loadings is also analyzed.