The mechanical behavior of the connections between the wall panels and the foundation determines the seismic performance of precast concrete shear walls. The post-tensioned connection, sleeve connection, lap-spliced connection, welded connection, and bolted connection are the most common today. However, they frequently have some shortcomings, such as the need for skill-trained workers, concealed work, engineering precision, high cost, and remarkable damage to horizontal joints. In order to overcome the shortcomings, a new precast reinforced concrete shear wall system with angle steel connectors was proposed and designed. Angle steel connectors were used to improve the shear resistance of the horizontal joints between the precast RC shear wall and the foundation, as well as to provide temporary support for specimen positioning and installation. Meanwhile, the angle steel connector can provide tensile resistance under extreme conditions such as a typhoon or strong earthquake. In order to investigate the seismic behavior of the new precast shear wall system, a full-scale precast RC shear wall specimen with angle steel connectors was built. Meanwhile, three full-scale precast RC shear walls with integral cast-in-place connections, grouting sleeve connections, and lap-spliced connections were designed and built to compare and investigate their seismic performance and mechanism. The results showed that the new precast shear wall system with angle steel connectors had improved seismic performance and deformation capacity. At the same time, the upward movement of the main crack was conducive to improving the bearing capacity of the shear wall. When compared to the grouting sleeve connection, it significantly reduced the amount of concealed work and made the construction quality easy to ensure. The seismic performance of the specimen with lapped steel bars and angle steel connectors was better than that of the specimen with grouting sleeve connection and cast-in-place specimen. The new precast shear wall system with angle steel connectors proposed in this study is well suited for use as a seismic resistance of building structures.