The aim of this research is to study the effect of rheological properties ,concentrations of non-Newtonian fluids, particle shape, size and the density difference between particle and fluid on drag coefficient (C) and settling velocity (VS), also this study show the effect drag coefficient (C)and Reynolds' number (Re) relationship and the effect of rheological properties on this relationship.P An experimental apparatus was designed and built, which consists of Perspex pipe of length of 160 cm. and inside diameter of 7.8 cm.