Acoustic emission technique possesses many advantages which are due in part to its noninvasive and relatively inexpensive.A set of apparatus was built to acquire the acoustic signals arising from impact of the glass beads dispersed in liquid with the container wall.The power spectrum of the signal was found to correlate linearly with the mass concentration of the beads,while the correlation of the power spectrum with the bead size is stronger than that with the bead concentration.The impact velocity calculated with FLUENT was used to estimate the bead size by fitting the power spectrum according to the principle of least squares.The fact that the estimated results are close to the average value over the specified size range shows feasibility of sizing solid particles dispersed in liquid by analysis of the acoustic signal arising from impact of the particles with the container wall.