An improved hyperbolic model of load-transfer for the pile-soil interface under deep excavation conditions was developed. It not only considered the influence on the initial shear stiffness because of excavation which decrease the normal stress of the surrounding soil, but also considered the influence of excavation depth, width and length of pile. A full-scale numerical experiment was completed on a single pile in sandy soil after excavation and the bearing capacity of pile foundation was analyzed using this model, and then the results was compared with the measurement and the calculating values, which were calculated from the traditional model. It was shown that the ultimate bearing capacity of pile foundation after excavation, which was calculated from both model, are closed to measurement. The tip resistance and shaft friction on the bottom of pile calculating from traditional model which cannot consider the contribution of soil for the pile tip behind the supporting structure, however, have significant differences compared with the measurement. So, the improved model is better to estimate the shaft friction and tip resistance for the pile foundation after excavation.