Abstract: The existing formulas for calcularing parameters such as incipient velocity, uplifted velocity, stopping velocity of sand and silt carrying capacity, etc. describing pattern of sediment transport are not suitable to studying various problems and are difficult to predict a tendency of sediment movement and to explain the formation of the pattern of sediment transport in the case histories such as sediment deposition and turbidity reduction caused by the submerged plants in the shallow lake. The quadrant analysis method has been applied to analyze the pattern of sediment transport in water flow recently. This paper explains a basic principle of this method and the way of using the method to analyze experimentally the measured discretized data of the turbulent flow structure. The method is applied to analyze the experimental data and explore the mechanism of turbidity reduction casused by the submerged plants. There forms a sweeping flow pattern bellow the canopies and the flow brings the sediment toward the bed surface, then the sweeping flow mixes with the sprinkler flow near the bed surface, thus the mixing process reduces the energy contained in the sweeping flow and promotes sediment deposition.