Abstract: A high-rise building with shear wall structure has been built to 27 floors above ground, and the actual strength of the shear wall concrete on the ground floor is lower than the design strength. The research used the unsupported shear wall replacement method to strengthen the shear wall. Based on field measured data and ABAQUS simulation, the vertical bearing capacity of the high-rise building shear wall during the unsupported replacement process and the seismic behavior of the shear wall after replacement were analyzed. The measured data and the study of 7 model specimens showed that the shear wall reinforced by segmental replacement method could meet the requirements of the bearing capacity of the shear wall during the construction process; after the reinforcement, there was a stress lag phenomenon in the replacement shear wall and different strength replacement construction of concrete had no significant effect on the stress lag phenomenon; 7 quasi-static simulation tests were performed by using 7 shear lag replacement shear wall model specimens, and the relevant seismic parameters of the one-time pouring shear wall under the original design were compared. With the improvement of the strength of the replacement concrete, the seismic performance of the shear wall reinforced by segmental replacement method was gradually improved, which could meet the original seismic design requirements.