To promote the resource utilization of industrial solid waste and the sustainable development of green wet-mix shotcrete, cement clinker-free solid-waste-based wet-mix shotcrete was prepared using steel slag, slag, and desulfurization gypsum as cementitious materials, and copper slag and waste rock as aggregates. Furthermore, raw material property analysis, mix proportion optimization, mechanical property testing, microscopic mechanism investigation, and on-site industrial tests were systematically conducted. The results indicate that the mechanical properties of the solid-waste-based wet-mix shotcrete with optimal mix proportions (specimens No.5 and No.9) are superior to those of the cement-based wet-mix shotcrete. The 7-day compressive strength of specimen No.9 reaches 16.31 MPa, and its 56-day compressive strength exceeds 28 MPa. Its workability is comparable to that of the cement-based wet-mix shotcrete, and the slump and slump flow meet the requirements of wet spraying operations. The solid-waste-based wet-mix shotcrete exhibits a remarkable solidification effect on heavy metals. It reduces the leaching concentrations of excessive heavy metals Pb and Cd in the copper slag to below the Class Ⅱ water quality standard for groundwater, demonstrating excellent environmental safety. Microscopic analysis results indicate that the solid-waste-based wet-mix shotcrete is rich in hydration products and exhibits a high degree of polymerization of the silicate gel. On-site tests verify the feasibility of engineering application for the copper slag wet-mix shotcrete. Although issues such as incomplete material discharge exist, they can be improved through process optimization. This provides an effective path for the harmless disposal and resource utilization of solid wastes such as copper slag, possessing environmental, economic, and social values.