Abstract: A new type of pile with rectangle and internal circular cross section is developed in recent years, which is named prestressed high strength concrete rectangular supporting pile (rectangular supporting pile for short). Compared with that of the pipe pile and square pile, the flexural stiffness of rectangular supporting pile is greatly improved in cross-section form. Thus it is more suitable to used as supporting structures in the excavation engineering in which the pile mainly bears horizontal force. An engineering case of the rectangular supporting piles used as the supporting structures of the excavation in soft soils is introduced, and the excavation is in good condition during its construction. The monitoring results indicate that the deformation of the supporting structures and the internal force of piles are in the controllable range. So the rectangular supporting piles have security assurance and greatly improve the economy and convenience for the pit excavation. Therefore this case study and the results may provide a reference for the application of rectangular supporting piles in excavation.