The implementation of the cost control of the project is an important responsibility of the project construction supervision. As the project construction supervision, it is not only necessary to establish a fair body, but also to constantly sum up experience from practice, explore the law of the project final accounting, so as to carry out strict and scientific cost control, in order to make the project final accounting audit work to be "fair", "reasonable" and "legal". Avoid the common mistakes made in the final account of project completion, such as "increase" not "decrease", "high" not "low", double calculation, miscalculation of quotas, etc., so as to lay a solid foundation for the project construction to pass the national audit smoothly.