This study measures the dynamic characteristics of flow control valve by a self-developed square pressure wave generator (SPWG). Comprised of a revolving shaft and a fixed ring, SPWG generates square pressure waves by the differential function of rotation between these two critical components. With the highly sensitive piezoelectric pressure sensor as the reference sensor, tests are conducted concurrently using a flow control valve. Under the same experimental parameters, the dynamic characteristics of flow control valve are evaluated by four kinds of system identification methods, namely ARX (Auto-Regressive with eXogenous input model), ARMAX (Auto-Regressive moving Average with eXogenous input model), OE (Output Error model) and BJ (Box-Jenkins model). The experimental results indicate that the dynamic performance of the tested flow control valve for resonance frequency, resonance peak and damping ratio are 1565.6 Hz, 0.9753 db and 0.4044, respectively.