Abstract: To efficiently and effectively enhance the seismic performance of brick masonry walls, spraying polyurethane technology is adopted. An unreinforced masonry wall and two reinforced masonry walls were designed and constructed to conduct horizontal low-cycle reverse loading tests. The effects of strengthening forms, including single-sided and double-sided spraying, on failure mode, hysteresis characteristics, backbone curves, deformation capacity, energy dissipation capacity and stiffness degradation of masonry walls were investigated experimentally. The test results show that spraying polyurethane can effectively limit crack propagation and delay stiffness degradation, significantly improve the deformation capacity and energy dissipation capacity of masonry walls, but it has limited impact on the load-bearing capacity and stiffness of walls. Compared with the single-sided spraying procedure, the double-sided spraying procedure is more effective in limiting the propagation of cracks and maintaining the integrity of the wall and further improving the hysteresis performance, deformation capacity and energy consumption capacity of the brick wall.