Abstract: A numerical analysis model of shear walls with mortise-tenon joints was established on the platform of finite element software ABAQUS. The influence of longitudinal reinforcement ratio of boundary element on mechanical behaviors of shear walls with mortise-tenon joints and low shear span ratio was studied. The results show that friction model can be used to simulate the new and old concrete interfaces of mortise-tenon joints. The calculation results of numerical analysis model are in good agreement with the test results, which can reflect the failure characteristics of shear walls with mortise-tenon joints. The bearing capacity of shear wall can be improved by increasing the longitudinal reinforcement ratio of boundary element, and the increase is more obvious when the reinforcement ratio is low. Vertical cracks occur along the lateral convex roots of shear walls with mortise-tenon joints, showing good deformation capacity. When the longitudinal reinforcement ratio of boundary element increases to 4.62%, brittle shear failure does not occur to the wall. When the horizontal reinforcement is 8@200, the longitudinal reinforcement ratio of boundary element exceeds 2.36%, the longitudinal reinforcement does not yield under the peak load, and flexural failure no longer occurs to the wall.