The existing building structure on a river bank affected the flood water area，which made it unable to meet the flood discharge requirements and needs to be rectified.A new type of sub-step vertical frame bank protection structure was formed after rectification. However，the load-bearing characteristics，instability mode and stability of the structure were still unclear.Based on strength reduction method，the bank protection structure in this paper was analyzed using ABAQUS. The calculation results showed that：1）The failure of this new type bank protection structure was mainly due to large sliding of the soil on the bank slope. And its plastic failure mode gradually expanded from the contact point between the bank slope and the beam-column frame and substructure slided prior to superstructure till plastic deformation transfixing. 2） The calculated structural safety factor of the bank slope was 1.69，which was greater than the safety and stability factor 1.25 specified by the code，indicating that the bank slope was currently in a stable state. 3）Overall the new type of sub-step vertical frame bank protection structure needed less materials，and the beam-column structure was beneficial to enhance the stability of the structure and the band slop. Thus it was certain cost-effective and feasible as well.