In view of the poor seismic performance of the ancient pagoda wall, a new seismic strengthening technology, strengthening the ancient pagoda wall with shape memory alloy wire (SMA wire), was proposed. In order to study the reinforcement effect, the mechanical properties of SMA wire were tested, and the influence of strain amplitude on its energy consumption was analyzed. The SMA wires were trained by loading and unloading to maintain a stable fully superelastic state. Then, the pseudo-static tests of two ancient pagoda wall models (one intact wall and one damaged wall) strengthened with SMA wire and one unreinforced model were carried out. The effects of SMA wire reinforcement on the seismic performance such as failure mode, hysteretic performance, bearing capacity, deformability, stiffness degradation law, ductility and energy dissipation capacity of historical masonry tower wall were studied. Test results show that SMA wire reinforcement does not change the failure mode of the wall, but can improve the brittle failure to a certain extent, can significantly improve the bearing capacity and energy consumption capacity of the wall, effectively limit the shear deformation of the wall and delay the wall cracking and stiffness degradation. Compared with the unreinforced wall, the bearing capacity and ultimate displacement of the wall strengthened with SMA wire increase by 16.91% and 22.65%, respectively. The bearing capacity and deformation capacity of the damaged wall strengthened with SMA wire are even greater than that of the intact wall. However, the stiffness and bearing capacity of elastic section and cracked section are obviously lower than that of intact wall.