A large-scale structural assemblage was tested under quasi-static loading to investigate the seismic performance of a rocking-wall structure assembled by precast members. An innovative PreWEC (precast wall with end columns) system, which consisted of a precast non-bearing rocking wall, energy-dissipating O-connectors, and adjacent load-bearing end columns was used as the rocking-wall system. The structure surrounding the PreWEC included precast edge beam and columns and a floor system formed by untopped precast planks. Wall-floor connections were used to isolate the floor from vertical movements of the wall. Test results showed that the floor was successfully isolated from the uplift of the wall throughout the test. The surrounding structure barely increased the strength of the PreWEC system, as anticipated. The entire specimen was almost damage-free at 2% design drift and demonstrated excellent self-centering performance even after experiencing 5% lateral drift. Design recommendations are provided for the key components of this type of precast rocking-wall structure (wallfloor connections, end columns, and floor-beam connections).