Abstract: The traditional measurements of the particle sizes and settling velocities of fine sediment need to be improved. This paper describes a method for the measurements adopting PTV technique. We conduct an experiment on the settling of non-flocculating fine particles, analyze the threshold for image binarization, and suggest that using a constant threshold replaces Otsu’s method. A set of particle matching parameters are selected by particle grade, image resolution, and sampling frequency, and the particle size and settling velocity are corrected using the Stokes formula to ensure a good accuracy of the measurements. In general, PTV is a feasible technique for measuring particle sizes and settling velocities of fine sediment, and this work lays a basis for further study.