Abstract:A new method is presented to analyze the vertical load bearing performances of prefab piles with opti2 mization and back analysis techniques. In combination with optimization theory , back analysis method and a new improved elastic theory method , a program is developed not only to stimulate the load2settlement curve ( Q2S curve) of static load testing , but also to analyze the soil mechanical parameters around the pile by using back analy2 sis method with optimization techniques on the basis of measured load2settlement information of static testing. This technique has been verified in large numbers of practical engineering with satisfactory result s.