With the increasingly severe situation of population aging in the society, home care will still dominate the development pattern of elderly care in the future, and the ageing-adapted renovation of the existing buildings has become a necessary link. In this paper, we design a spatial configuration strategy for ageing building design, firstly, we use graph theory algorithm to limit the topology of the plan layout form, and under the influence of the tensor field model constructed by the geometric contour of the site, we realize the evolution of the overall layout of the building plan based on the geometric conditions of the site. Then, based on the BIM digital modal information, the topological relationship of the building interior space is extracted, the optimization design objective of the building interior space is determined, and the derivative design method with the core of the Improved Small Habitat Genetic Algorithm (IPSO-NGA) is applied to carry out the multi-objective optimization, to obtain the best optimization design scheme of the building interior space and to analyze the optimization results to verify them. The experimental results show that the overall index state of the collaborative performance change of the BIM model based on IPSO-NGA is within the controllable range, and the global reliability test curve is smooth, the fluctuation amplitude is small and gentle, and the fluctuation frequency is regular. The method in this paper is able to find the optimal solution for the optimization of space design of the aging building, and the optimal building scheme is more reasonable, with higher application value, which can satisfy the needs of the elderly for home care, and has high research value and market promotion value.
