Abstract: The 3D flow field and turbulent characteristics of an open channel confluence at junction angle 30° with different discharge ratios are studied by means of ADV in the channel model test. The test results indicates that a discharging area and a return flow separation zone occur in the 3D flow field of the confluence region, thus resulting in greatly changing the distributions of velocity and pressure as well as turbulent characteristics in comparison with an unitary channel, and that the maximum value of fluctuating intensity occurs at the point of z/h=0.2near the right-side of releasing region of downstream confluence inlet.