Based on Xi 'an Metro Line 14 Shield Crossroads Daxi High-speed Railway Extraordinary Bridge Pile Group Foundation Project, 3D numerical simulation and field monitoring are adopted. In this paper, the influence of shield tunnel construction through super-long pile group in short distance and the reinforcement scheme are studied. The results show that the displacement change of the front pile is greater than that of the back pile, the vertical displacement is negative, and the settlement of the bottom pile is greater than that of the top pile. The horizontal displacement changes mainly in the tunnel depth and above, and the maximum bending moment and axial force of the pile appear in the corresponding position of the tunnel vault. Under the working condition without partition and reinforcement measures, the maximum abutment settlement is 4.19mm, which exceeds the control index. The effects of the three proposed reinforcement schemes show the following rules: Sleeved valve pipe grouting reinforcement < borehole cast-in-place pile partition < grouting + partition pile + steel transverse support comprehensive reinforcement, the comprehensive reinforcement scheme has the best effect on pile displacement and internal force optimization, horizontal and vertical displacement, axial force and bending moment are reduced by 65%, 20%, 80% and 50% respectively, and the maximum abutment settlement is 1.47mm, meeting the control indicators.