The mortise-and-tenon joint is a main structure widely used in traditional Chinese wooden furniture. The material of antique wood furniture is perishable and prone to swelling after water absorption. Furthermore, mortise-and-tenon joints have diverse geometric features, which result in complex local stress states that may cause the tenon to be easily fractured or pulled out. To solve these problems, for Ming and Qing furniture collected in Shanghai Museum, relevant repair schemes were proposed according to the type of damage to the furniture. Then, the mechanical principle in the existing repair scheme of mortise-and-tenon joint and its rationality were elaborated on by continuum mechanical analysis, numerical simulation and performance tests. Finally, based on the mechanical model developed, the existing repair scheme used in the museum was optimized.