Abstract:A controllingactivity based model was proposed to estimate the construction duration of terminal megaprojects from the consulting achievements of project timecontrolling for more than ten airport megaprojects in China (2000—2016). First, typical construction sequences of controlling activities for each possible critical path were determined, and the distributions of nonoverlapping time between controlling activities were fitted. After that, based on fitting the duration distributions of four possible critical paths, a model for predicting the duration of terminal building was proposed and applied to three completed terminals. The results show that the proposed model reasonably predicts the construction duration for the case projects. Compared to traditional risk planning methods, the model proposed simplifies the complex work.