Abstract: A method for measuring parameters of solid phase of slurries having the following steps: forming ultrasonic oscillations and emitting them into a fluid under study, forming the Lamb waves and directing them into a wall of a vessel containing the fluid under study, forming acoustic currents and radiation pressure of sonic radiation in the fluid under study, and measuring amplitude and length of pulses of ultrasonic oscillations that pass through the fluid under study and the Lamb waves that pass through a predetermined distance along the wall of the vessel containing the fluid under study without and with the action of the acoustic currents and radiation pressure of sonic radiation, the values of which are used for the assessment of concentration of solid phase of the fluid under study. An apparatus for carrying out the method has two measurement channels each having a logarithmic converter, a subtraction unit and a division unit.