Abstract: Water-filled impedance tube is an important platform for sound absorption measurement. For the test system with monostatic transducer, the common used signal is the pulse modulated sine-wave, which is essentially a single frequency measurement. In order to implement broadband sound absorption measurement, an impulsive sound is generated in water-filled impedance tube, and a time sequence control system is designed for the monostatic transducer generating the impulsive sound and picking up the echo-signal. The principle of sound absorption measurement is explained and a test example is shown.