he construction period cost includes two aspects: one is the cost of the measures taken by the project management department to ensure the construction period; the other is the owner's claim cost caused by the construction period delay, which can also be called the construction period loss. Due to the limitation of internal and external environment and contract conditions, it is a very difficult task to guarantee the contract period and reduce the cost. Therefore, we must correctly deal with the relationship between the cost of construction period measures and the loss of construction period.