In recent years, with the continuous development of urbanisation, the proportion of interior design in public buildings has been increasing year by year. At the same time, there is a tendency in many places for the interior spaces of public buildings to be upscale and retro. This indicates that people are paying more and more attention to the spiritual aspect of their lives, in addition to the materialistic pursuit of enjoyment. The current phenomenon of overdecoration in society can lead to excessive luxury and wastefulness. In these wasteful interiors, the beauty of the building itself is lost. In addition, this type of interior design is not only expensive but also poses certain safety risks to some extent. In the modern society, public buildings are essential places for public activities. To be specific, they are closely linked to public services and social management attributes. As a result, public buildings usually play a decisive role in facilitating communication and cooperation between various persons. Thus, the construction requirements of public buildings are currently increasing and the structural shapes of buildings are becoming more complex. In addition, the level of technology and the use of public buildings are becoming increasingly demanding. As a result, it is quite important to examine how modern and emerging technologies can be applied to public building design in order to improve its effectiveness. At the same time, with the continuous and rapid development of China’s economy and the promotion of the concept of environmental protection, the greening of public buildings has become an object of concern and research. There are many different types of existing public buildings in China, and in the design process, the energy consumption of the building throughout its life cycle and its impact on the surrounding environment are not fully considered, resulting in problems such as high energy consumption and poor indoor comfort in the actual use of the building. However, the demolition and reconstruction of buildings can lead to waste of resources and environmental pollution. Therefore, it is feasible and necessary to study the application of green building technologies in the design of public buildings. This study models the effectiveness of public building interior design based on BIM technology from the perspective of integrated design as well as parametric design. This model enables the interior design of public buildings to become energy efficient, emission reducing, and environmentally sustainable. After all, the integration of architecture and interior design can reduce unnecessary decorative waste. In addition, this model can also respond to the government’s efforts to develop an ecological civilisation, creating a new way of living that is resource efficient.