Based on Jinggangshan-Ji’an railway overpass bridge of Shenzhen bridge in Jinggangshan economic and technological development zone in Ji’an city, Jiangxi province, according to characteristics of bridge overpass railway and karst formations developing in situ, some technical measures are proposed to solve the difficulties in the design and construction of bridge pile foundation in complicated karst stratum. The measures include an elastic wave CT method in detecting karst conditions, the use of super large diameter hollow pile foundation to replace bored pile, and application of grouting reinforcement under foundation bottom. The proposed measures can solve pile problems in complicated karst formations, and φ15 m super-large-diameter hollow pile is also the largest diameter pile foundation in bridge.