The high-pile wharf structure is damaged to various degrees during the service life and the safety of structure is degenerated.To ensure the long-term safe operation of wharves，it is necessary to monitor their operating state and timely forewarn the risks through real-time monitoring.In this paper，a forewarning model of high-pile wharf structure safety monitoring is proposed，and design control values of different structural states are used as the forewarning thresholds of different levels.Each level forewarning value corresponds to different risk levels，and the disposal measures are proposed for different-level forewarning.The forewarning model is applied to monitor safety of a high-pile wharf in Nanjing Port，including displacement of the wharf structure and strain of the piles under variable load in real time，and the three-level safety forewarning thresholds of the displacement of the wharf structure and the strain of the piles are calculated and set.The results show that the setting of wharf safety forewarning threshold and the countermeasures of safety alarm are scientific and effective，which can realize the purposes of overall technical state assessment and safety forewarning of all the operating condition of the wharf structure.