This study developed a square-like pressure wave generator as an excitation source to test dynamic characteristics of pressure sensors. The developed generator can generate a square-like pressure wave of as high as 2 kHz and can achieve high-frequency switching by utilizing the differential principle through a series of mechanical rotations between the revolving spindle and revolving ring. The square-like pressure wave generated is input into the hydraulic system while the output voltage signals given by the pressure sensor can be analyzed by spectrum analysis to obtain dynamic characteristics of the pressure sensor.