Construction stage engineering cost control key should start from the supervision engineer or construction unit and construction unit of the work in two aspects, one is for the supervision of engineering and construction unit of the engineering change should be in accordance with the "construction project construction contract demonstration text" the provisions of the strict examination and approval, management and control, put an end to irrational and unnecessary changes, and must be done before the construction, avoid the phenomenon of change after construction. Construction units should be based on site management, strengthen the process control, for construction safety, schedule, quality, and money the best combining site, continuously explore ways to reduce the engineering cost, to pay special attention to each link of cost control work, such as labor, materials, machines, change visa, project claim, etc., raise the level of enterprise construction phase of the project cost management, make the enterprise obtain satisfactory economic and social benefits.