In construction management process, the thought of supply chain management has been used more and more, which has made great achievements, but brought many problems as well. For instance, the contradiction between reducing the risk of interruption and reducing the inventory costs. In order to find the balance point between these two situations, the paper introduces a costs model of emergency strategies for the construction enterprises. By optimizing the model, it has obtained the optimal standby contract quantity and the optimal quantity of safety stock. The result also shows that the possible high costs from loss on work stoppages and the high management costs from standby supplier, are under the influence of two different factors-safety stock and order quantity of standby contract in supply disruption. Therefore, both optimal safety stock and optimal order quantity of standby contract are subject to the costs caused by the standby supplier management and the costs caused by loss on lockout.