The cost control of construction projects directly determines the profitability of construction projects. Building information modeling (BIM) technology came into being with the development of modern science and technology, through BIM technology can effectively solve the problem of cost control of construction projects, therefore, the specific application of BIM technology in the cost control work of construction projects is a topic worth studying. This paper mainly outlines the main points of BIM technology and cost control of construction projects, and sets the evaluation indexes of RM, PM and CCD according to the key processes of sub-parts of projects, and evaluates which sub-parts of projects are used in combination with BIM technology as the key processes of cost control of construction projects through the coupling relationship between them, which can significantly reduce the construction cost of construction.