The commonly used construction techniques for the enclosure structure of deep foundation pits that do not enter the rock include row piles, occlusal piles and underground diaphragm walls. Based on the foundation pit enclosure project of Milesi Station of Kunming Rail Transit Line 5, the construction technology comparison and selection of the project is carried out considering the factors such as formation adaptability, construction efficiency, project cost and quality control of different construction technologies. The results show that: (1) Row piles or secant piles can not meet the requirement of passing through the hard round gravel layer; (2) Row piles are difficult to realize the impermeability requirements; (3) Underground diaphragm walls may cause high cost and poor economy. Finally, the construction technology of the project was determined with the underground diaphragm wall as the main and the occlusal piles as the auxiliary was finally determined.