Abstract: To examine the velocity measuring capability of Acoustic Doppler Velocimeter (ADV), especially for the low-velocity flows, the SonTek 16M MicroADV was taken as an example and the independently developed towing tank with high-precision velocity calibration facility was employed. During the tests, the indication errors for the velocities were measured. Besides, the influences of the signal intensity, the sampling frequency were analyzed on the velocity measuring capacity. The results verify that MicroADV can well indicate velocities with the relative errors smaller than 1% and absolute velocity errors not larger than 2.5 mm/s when the signal-noise ratios are above 15 dB in high-frequency sampling cases. As the sampling frequency increases, the measuring capacity for the time-averaged velocities will be influenced. Once the sampling frequency increases above 10 Hz, the probability that the measuring errors of the time-averaged velocities exceed 1% will become larger.