To investigate the high-value and high-dose utilization of solid waste gasification ash in concrete components, low-cycle reciprocating loading tests were performed on joints within one ordinary concrete and three gasified ash concrete beam-column joints. The failure modes, hysteretic behavior, energy dissipation, ductility and stiffness degradation were studied. The failure mechanisms of concrete joints with coal ash as an admixture were explored, and the effects of dosage, axial compression ratio, as well as concrete strength on the seismic performance of these joints were analyzed. The results reveal that plastic hinge failure at the beam ends occurs in all of the coal ash slag concrete joints. During this process, the reinforcement yields and the concrete is crushed, which includes four stages: initial cracking, extensive cracking, ultimate strength and failure. The hysteresis curves of the specimens are relatively full. When the dosage ratio of coal ash slag is 20%, the bearing capacity of joints made with coal ash slag concrete increases by 14% compared to those made with ordinary concrete.Using proper designed coal ash slag concrete can improve the bearing capacity while conserving cement, and lowering carbon emissions in concrete, which provides some reference for the large-scale and high-value utilization of solid waste coal ash in concrete engineering.