Aiming at the problem of the low accuracy of Acoustic Doppler Velocimetry (ADV) used in clear water flow, a method of mixing suspended particles into the clear water is presented to improve the accuracy of ADV. By comparing the measurement results of ADV in the water flow with mixed suspended particles and the clear water, it is observed that the flow velocity of the former situation is obviously more stable, the result meets with the actual stable uniform flow of the water flume. The suggested content of the suspended particles in this test is 106 g/m³. Ten velocity measuring points are arranged vertically in the water flume. The flow velocity is changed by adjusting the frequency of the converter of a pump. This method is used to measure the vertical distribution of the flow velocity of the water flume. It is observed that the flow velocity is not uniformed along the vertical direction, and is followed the linear shear flow distribution. The reasons for this uneven distribution are the arrangement of outflow port and the friction of the lateral and bottom walls of the water flume. Finally, the linearly relationship between the frequency of converter and mean vertical velocity is presented by the means of least square method.