A single-layer gridshell is a shape-resistant structure, where the structure’s shape and grid division are designed in a way that reduces the bending effect caused by loads, allowing members to bear axial forces as much as possible to fully utilize the material’s potential. This results in a lightweight and transparent structure that spans large distances. As the intersection points of members, joints not only have complex loading conditions but also have a significant impact on the structure’s overall performance. First, the joint’s stiffness affects the distribution of force flow, thereby affecting the structure’s stiffness, static stability, and other mechanical properties. Second, if a joint fails, force flow will be interrupted, causing a change in the transmission path, and may even lead to the collapse of the entire structure. Therefore, the current design code recommends only a limited number of joint types, and joint size design tends to be conservative. In summary, there is an optimization space for the joints of single-layer gridshells under the premise of ensuring their safety and reliability. This chapter begins by reviewing the basic components of a joint, clarifying the core part of the joint optimization design—the joint core. In order to improve the rotational stiffness of the joint, a rotational stiffness optimization model of the joint core was established, and the topology optimization method was used to optimize the joint core under the premise of meeting all design requirements. At the same time, a universal connection interface was designed by combining structural design, which can meet the connection requirements of the members in different orientations. In order to improve the safety performance of the joint, a safety performance evaluation index of the joint was first defined. Based on this index, a joint safety performance optimization model was established, and an optimization algorithm program was compiled to perform topology optimization on two-dimensional joints.