For a better study on the seismic performance of short-limb shear wall coupling beams after earthquake, two short-limb shear wall models with coupling beams are designed with a ratio of 1:3. Firstly, the original specimens are subjected to the same degree of preload loading until they are destroyed, with the shear failure occurring in both specimens. The carbon fiber-reinforced polymer (CFRP) mesh and composite mortar are used to reinforce the two specimens according to the fracture mode and the position of failure. The ultimate bearing capacity and deformation of the strengthened specimens can be obtained by low-cycle reciprocating loading tests, followed by an analysis of the hysteretic and ductile properties of the specimens under different working conditions. The results show that the bearing capacity, ductility and energy dissipation capacity of the specimens have been significantly improved by the CFRP mesh reinforcement, with the degradation rate of stiffness slowed down. The research conclusion and the proposed reinforcement method are of valuable significance for the shear reinforcement of the actual engineering coupling beam due to the lack of stirrups to improve the seismic performance.