Abstract: With the construction of a number of high-head, high-flow and high-arch dams, the reasonable design of plunge pools has become a major technical problem in engineering design, and the dynamic water impact pressure is an important indicator of the design of high dam cushion pools. The piezometer method is a more economical method commonly used in the current hydraulic model test. In order to evaluate the sensitivity of the piezometer to measure the dynamic water impact pressure, we used a three-dimensional turbulent flow numerical simulation method to analyze the effect of dynamic water impact pressure measurement in a cushion pool under different ratios of the inner diameter of the pressure tap to the inner diameter of the piezometer. The results show that the ratio of the inner diameter of the pressure tap to the inner diameter of the piezometer has a greater impact on the measurement of the dynamic water impact pressure, different from the conventional hydraulic model test requirements (the inner diameter of the pressure tap should be less than 2 mm, and the inner diameter of the piezometer should be greater than 6 mm). It is recommended that the ratio of the inner diameter of the pressure tap to the inner diameter of the piezometer should be greater than 0.7 and the inner diameter of the piezometer should be greater than 6 mm, and for the core area of the impact, the pulsation pressure sensor method should be combined with.