Abstract: Convergence deformation overrun is a typical disease of subway shield tunneling in soft soil area. Currently, the industry mainly adopts the reinforcement of bonded steel ring, but the reasonable reinforcement opportunity of which is not clear. In view of this, a refined finite element model of 3D shield tunnel is established, which can reflect the interfacial bond slip failure, and the convergence deformation of lining ring after reinforcement, the joint opening, bolt stress and internal steel ring stress under different previous shield tunnel deformation conditions are studied. The results show that: ① when the lining ring reaches yield after the reinforcement of bonded steel ring, the stress level of steel plate has not reached the strength limit of the material itself, but some of the interface has been stripped off; ② the reinforcement opportunity has a significant impact on the deformation and failure characteristics of the reinforced lining ring structure. In conclusion, the most reasonable time for steel ring reinforcement should be a safety boundary. Earlier or later than safety upper limit, the deformation and failure of lining ring structure will have a strong suddenness or produce an excessive deformation.