With the rapid advancement of 3D printing technology, one of its widely adopted practical applications is the assembly of buildings using 3D-printed modular components. This method involves printing structural element formworks and subsequently casting concrete and arranging steel reinforcement within them to achieve reinforced 3D-printed concrete (3DPC) components. Therefore, research on connectors between modular structural components, i.e., 3DPC shear keys, is particularly important. Given the limitations and complexities of experimental studies on 3D printing, establishing a three-dimensional finite element model capable of accurately capturing the mechanical behavior of 3D-printed components is also crucial. This paper provides a brief overview of the research group’s previous large-scale experimental studies on 3DPC shear keys. The commercial finite element software ABAQUS is used for modeling and analyzing of test specimens, leading to the establishment of a finite element model suitable for 3DPC components that accounts for multi-interface conditions. By considering different interface behaviors, the analysis results indicate that the model incorporating both interface cohesion and friction behavior yields the most accurate predictions with an average predicted-to-experimental ratio of 0.99 and 0.86 for peak load and deflection, respectively. Besides, lower key angles show higher shear strength due to the longer contact path and higher normal force at the interface, which leads to higher friction and interfacial force with an enhancement in shear strength of 10.4%. These findings establish a reliable modeling framework for precise evaluation of 3DPC joint performance, thereby providing actionable guidance for optimizing modular connections in prefabricated construction.