The dynamic balance of sediment elevating and settling in the turbulence field of a river channel is an outcome of two aspects: one is the cycling process of the bursting and weeping of a turbulence that makes the sediment suspend from the channel bed surface in the turbulence field; the other is the gravity of the Earth that makes the sediment fall down. In order to quantitatively express the turbulent flow functions such as the bursting and sweeping, momentum transfer and energy consumption onset of turbulence, and the ability to suspend sediment in the turbulence field, the nominal eddy named “Ω” eddy, as a representative eddy in the turbulence field, is defined and endows it with the functions, whose spatial dimension moving along the water depth in the turbulence field is 3/2 and nominal dimension and quantity are derived. Then, the momentum principle of water and sediment movement in turbulent field is established. For the dynamic balance state of sediment suspending in the turbulent flow field, an energy relationship for the sediment suspending is derived, which is proved that 25% of the vertical (gravity direction) component of the momentum in turbulent field is transferred to sediment particles for jumping and suspending. Thus, the formula of sediment carrying capacity of the channel water flow is derived which does not need to be calibrated by observed data and can be directly used for the calculation of sediment transportation. The study has both theoretical significance and engineering value.