In order to provide a good solution for the treatment and utilization of construction waste, especially waste concrete and to promote the development of green construction to some extent, in this paper, a new composite shear wall filled with demolished concrete lumps (DCLs) and self-compacting concrete (SCC) was proposed, and its seismic performance after fire was investigated. Based on quasi-static tests of four composite shear walls filled with DCLs and SCC, three after a standard fire and one contrastive specimen without fire, the effects of fire exposure time, fire-retardant coating on the edge constraint steel pipe column, and the width-thickness ratio on seismic performance of composite shear walls after fire were studied. The failure patterns, bearing capacity, hysteretic loops, ductility, skeleton curves, rigidity degradation curves, and energy dissipation of shear walls were analyzed and compared. Test results indicate that the bearing capacity of the shear wall after 60 min of standard fire is slightly lower than the contrastive specimen without fire, but specimens still have good seismic performance. The interlayer displacement angle of the shear wall after a fire still meets the requirement of regulations. The fire-retardant coating on the edge of concealed steel pipe column has a limited effect on the seismic performance of specimens after a fire. The horizontal bearing capacity and energy dissipation capacity of shear walls after a fire can obviously be improved by properly increasing the width-thickness ratio.