A new method of zeta-potential measurement by the use of the liquid sedimentation balance method is developed. The test samples used were spherical acrylic and silica particles, and beads mill was used to enhance particle dispersion. The new method can be used to estimate the zeta-potential of each particle size range. The absolute value of the negative zeta-potential of small particles is greater than that of large particles. The results of measuring zeta-potential by the new method agree with other conventional measurement devices. The slope of the zeta-potential with respect to particle diameter decreases as the waiting period following the beads mill pre-treatment process increases. (C) 2012 Elsevier B.V. All rights reserved.