The excavation of foundation pit above the existing metro tunnel inevitably leads to the uplift of the tunnel. As an anti-uplift measure, the anti-uplift portal frame is still lack of research. Based on a foundation pit excavation project colinear with tunnel for long-distance, the excavation influence on the underlying shield tunnel during the construction process of anti-uplift portal frame and the foundation pit excavation was studied via numerical simulation. The interaction mechanism between the anti-uplift portal frame and ground as well as the anti-uplift effect were analyzed. Finally, a structural optimization design was proposed based on the simulation. The results show that the tunnel may be uplifted due to the shaft excavation during the construction of the anti-uplift portal frame and the uplift can be effectively restricted by backfilling and sectional excavation. Compared to the excavation without the anti-uplift portal frame, the uplift value of the tunnel decreases from 19.5 mm to 15 mm because of the restriction of the anti-uplift portal frame. The connection between the slabs and piles are weak positions of the structure due to the stress concentration and it is necessary to do a local reinforcement treatment in the connection.