Abstract: Field ADV measurements of suspended sediment concentrations have been taken in the Zhongxian and Fengjie reaches of the Three Gorges Reservoir, which are suffering from serious sediment deposition. From these field data, we have developed an inversion method for instantaneous sediment concentration. ADV acoustic signals are usually contaminated by spikes and high-frequency noises. To despike the signals, this method adopts wavelet analysis to filter out their high-frequency noises, and then processes them using a phase-space density method. Calibration of sediment concentration versus acoustic intensity in double logarithmic coordinates shows a linear relationship whose slope and intercept are both functions of particle diameter, thus providing an inversion formula for instantaneous sediment concentration. Calculations using this formula reveal that turbulent sediment fluxes are closely related to the Reynolds stresses and the scalar spectrums of sediment concentrations follow the Obukhov-Corrsin law of -5/3 power. The results indicate that our new inversion method for instantaneous sediment concentration is feasible and effective.