The foundation of Hong Kong International Airport (HKIA) is fill soil with high water table. It is very important to choose the appropriate support structure for the underpass foundation pit project. This paper proposes the inclined vertical combination type locked steel pipe piles, which is beneficial to support, waterproofing and recycling. Based on Midas GTS NX,Numerical simulation was carried out to compare and analyze the engineering response of the inner row of piles of the inclined vertical combination type double-row locked steel pipe piles with different combination type and inclination angle.The results show that the inclined vertical combination type double-row piles have better engineering effect than the traditional double-row vertical piles in the process of foundation pit excavation. When the inclination angles of the inner row piles are the same, the horizontal displacement of the top of the piles and the peak bending moment of the pile body of the inner row piles of the positive-negative inclined double row piles are minimized. In the project, the double-row locked steel pipe piles can be preferentially set into positive-negative inclined double-row piles and internal inclined-vertical double-row piles, and the inclination angle can be increased as much as possible within the allowable range of the construction equipment, so that the horizontal displacement at the top of the piles and the peak bending moments of the piles of the internal row piles can be minimized. The results of the study can provide a design basis for the excavation support of underpass foundation pit in filled soil site with high water table.