In the context of the dual carbon strategy and the transformation of the building sector, the industry has become more and more energy consuming and emitting. The integration of green and low carbon principles into the whole life cycle of a building project is a necessary requirement for industrial development. In this paper, the core nature of green and low carbon concept is defined, and the standards for the division of project process are set up. It systematically analyses the gaps in the implementation of these principles at key stages–planning, design, construction, operation and maintenance, and outlines the basic principles for their integration. Targeted optimization approaches are proposed in three dimensions: enhancing standard systems, applying low carbon technologies, and setting up sustainable governance mechanisms. The purpose of this research is to reduce energy consumption and emissions in building projects, and to provide theoretical and practical advice for the construction industry to develop green, low carbon and high quality.