Driven by the green building concept, assembly building technology has gradually become an important direction for the transformation and upgrading of the construction industry. At the same time, the development of construction waste recycling technology provides a new way to solve the problem of construction waste disposal, and the application of recycled materials in the assembly building system can not only reduce the construction cost, but also reduce the environmental load and realize the goal of sustainable development. In this paper, a synergistic efficiency system of low-carbon assembled toilet system is constructed by combining the standardized modular design of integrated smart toilets with the application of recycled concrete. The study used ABAQUS finite element software to establish a numerical simulation calculation model for the seismic performance of the energy-consuming combination wall, analyzed the performance of recycled concrete using the concrete damage plasticity model, and realized standardized production through the principle of modular design. The test results show that the ultimate load of the roof cover reaches 109.72kN, the initial stiffness is 4.5kN/mm, and the energy-consuming capacity of the KJ-6 node is 12.2 times higher than that of the empty steel frame. The technical and economic analysis shows that the total cost of Project A with recycled concrete composite thermal insulation blocks is 1055.14 yuan/m², which is 48.6% lower than that of traditional concrete Project B of 2054.72 yuan/m², and the thermal insulation cost only accounts for 1.36% of the total project budget. The study shows that the modular design of the integrated smart toilet combined with the application of recycled concrete significantly reduces the construction cost and improves the efficiency of resource utilization under the premise of ensuring the structural safety performance, which provides technical support and economic feasibility verification for the development of low-carbon assembled buildings.