Artifical intelligence methods are implemented to simulate the behaviors of axially and laterally loaded piles using the field observation tests data obtain ed f rom the drilled shafts and driven piles.The optimal neural network model is deve loped using only simple input data of SPTN values and piles' geometrical featu r es etc..The analysis for R.C piles of some projects is performed adopting the BP N N and GRNN models respectively,and the obtained predicated results are compared w ith the data from conventional design method.It demonstrated the obvious advanta ges of neural networks in the design of pile foundations over the traditional me thods.This paper has an important practical significance and a referential worth iness in the design of pile foundations.