Abstract: Based on the previous study on the flow phantom,the scheme of designing the flow phantom is introduced,which includes selecting the pump,molding the tissue-mimic,and making the blood-mimic.After putting this component together,the Doppler signal can be collected from this flow phantom by the ultrasound sensor.Then,its time-frequency figure can be obtained using the conventional algorithm,the STFT (Short Time Fourier Transform),to process it.From the calculating results based on the algorithms above,some useful information can be got:firstly,the power spectrum distribution is related to the flow speed in one pulsatile flow cycle;secondly,the frequency offset is also related to the flow speed.