This study focuses on the stability of the excavation face during the double-mode shield crossing the fault zone under the Pearl River. The Hongshengsha Station-Yufengwei Station section project of the second phase of Guangzhou Metro Line 7 was used as a case study. Numerical simulations were conducted to analyze the whole area and the local high-risk area of the shield crossing fault zone. The study explored the risk of the shield crossing process and the influence of different support stress and grouting pressure on the stability of the excavation face and stratum deformation. The tunneling parameters analysis was used to evaluate the rationality of numerical simulation. The results show that: (1) When the excavation surface is distributed in the upper-soft and lower-hard strata, the shield tunneling is likely to cause large stratum settlement. When the stratum distribution is upper-hard and lower-soft strata, it is easy to produce large stratum uplift; (2) The stability of the excavation face should be considered in the weak local stratum when the shield passes through the composite stratum. The weak stratum deforms towards the inside of the tunnel when the supporting stress is less than the static earth pressure in the weak stratum, and the deformation increases with the reduction of the support stress ratio; (3) The grouting pressure has no effect on the stability of the excavation face but is inversely proportional to the formation settlement. The greater the grouting pressure, the smaller the ground settlement. The shield tunneling verified the correctness of the numerical simulation results. The Search results provided technical and theoretical guidance for similar engineering construction.