Abstract: In this paper, a systematic study is carried out on the problems of high water pressure leakage, failure of shield tail seal, water and sand gushing, breakdown of river bottom, mud cake of cutterhead, formation instability and settlement control faced by large-diameter shield tunneling in deep soft soil layer with sand in the Pearl River Delta region. Firstly, the dynamic optimization of tunneling parameters is improved through the targeted transformation design of slurry balance shield machine. Secondly, through the settlement monitoring of different depths of the tunnel top stratum, the multi-stage grouting is guided to control the settlement, and a set of technical system for safe crossing of large-diameter shields suitable for this special stratum is formed, which has been successfully applied to the crossing project of Maolong Waterway. During the construction period, the settlement of river embankment and tunnel vault was monitored in real time by setting monitoring points. The results show that the settlement of river embankment caused by shield construction is divided into rapid settlement stage and stable settlement stage. The maximum uplift is 1.56 mm and the maximum settlement is 10.65 mm. The segment is generally uplifted, and the maximum uplift of the vault is 2.7 mm. The deformation is controlled within the allowable range, which verifies the effectiveness of the adopted technical measures and effectively guarantees the smooth construction of intercity rail transit. The technical measures can provide reference for similar projects.