With the rapid development of economy and society, steel pipe micro-piles as a support structure are used more and more in the deep foundation pit. According to the construction technology and field use of the steel pipe micro-piles, this paper summarizes the main characteristics of the steel pipe micro-piles applied in the foundation pit support works, analyzes the role and effect of the steel pipe micro-piles in the foundation pit support works with regard to the field cases. It is demonstrated that the advantages of the micro-pipe steel piles can be fully exploited in the foundation pit support works in case of the limited surrounding environment conditions of the foundation pit, emergency reinforcement, etc. with significant economic and social results.