This study was a preliminary examination to investigate the effect of particle sizes on detergency of particulate soil. Monodispersed spherical $alpha-Fe_2O_3$ particles were prepared by hydrothermal aging of an acidic $FeCl_3$ and HCl solution. The $zeta$-potential of $alpha-Fe_2O_3$ particles was measured by microelectrophoresis method, and the potential energy of interaction between particles was calculated by using the heterocoagulation theory. The particle size was reduced with decreasing concentration of $FeCl_3$ and with increasing concentration of HCl. The $zeta$-potential of $alpha-Fe_2O_3$ particles and energy of interaction between particles were increased with decreasing particle size and increasing concentration of surfactant. But the dispersion stability of particle increased with decreasing particle size and concentration of surfactant. The dispersion stability of particle was not related to interfacial electrical condition in high concentration of surfactant solution. Such phenomenon entails some sort of interaction between interfacial electrical effect and steric stability by adsorption of surfactant.