This paper analyzes and summarizes the difference between BIM technology and traditional methods in cost management, subdividing the cost index of construction projects into elemental price index, bill of quantities price index, index cost index, and calculating dynamic cost index of construction projects. Based on the cost performance index and schedule performance index, the schedule-cost two-dimensional model of BIM technology is formed to complete the assessment and control of cost performance in order to realize the value analysis of BIM technology in the dynamic cost management of the whole process of construction engineering. Analyze the dynamic cost management of BIM technology in the decision-making stage, design stage, and construction stage of construction projects with examples, focusing on the exploration of engineering cost problems in the construction stage, and analyze the project benefit rate of cost management with BIM technology. Through BIM modeling for collision and error checking and deepening the construction stage design, a total of 503 design collision and error problems are found in total, 15 design change orders are reduced, and about 1,629,480,000 yuan of economic benefits are generated.