In order to get the moment of retaining pile during the excavation and the regulation of lateral displacement changing with excavation depth, comparative analysis was made on the internal force and displacement of retaining pile both with and without steel support during the excavation in different crossing-sections. Two-dimensional analysis was made on the excavation soil in Zhongjie Station with PBA method by MIDAS-GTS to determined the location and the spacing of the steel support and the conclusion was got that the largest moment of piles and the displacement would be reduced 278% and 317% respectively with steel support.