Abstract: The physical model of flow carrying sediment is analyzed based on the previous research findings. The expressions of the terms of turbulent production and viscous dissipation are obtained taking the turbulent energy equation of flow carrying sediment as a theoretical base, then a universal formula of sediment-carrying capacity for turbulent flows at smooth, transitional and rough zones is deduced. The formula is verified by the field and experimental flume data, and the influence of the main factors on sediment-carrying capacity is analyzed.