The mean square error of vibration displacement is one of control indexes of sluice pier′s vibration hazard assessment. In order to obtain the whole dynamic displacement field of the flood discharge vibration of the pier, this paper takes Shuhe hydropower station sluice pier as an engineering example to evaluate the comprehensive vibration hazard of the sluice pier. In view of the fact that the sluice pier has caused strong vibration during the flood discharge which leads to operate abnormally, the flood discharge vibration prototype test is carried out. Moreover, a method of inversion of the whole dynamic displacement field of the sluice pier is proposed based on particle swarm optimization algorithm and the limited measuring point displacement. The results show that the inversion of the dynamic displacement field of the sluice pier structure is achieved by using only eight points′dynamic response of the top of the sluice pier, and the fitting degree is higher between the inversion value and measured value. Therefore, it can provide a support for the comprehensive evaluation of vibration safety of sluice pier during flood discharge.