Sedimentation field-flow fractionation (SdFFF) is a well-known method for the separation and characterization of particulates and colloidal materials. In SdFFF, the separation is conducted by the combination of centrifugal force and parabolic laminar flow in a ribbon-like channel. In this research, polystyrene latex standards were selected as the sample materials. The particle retention behavior was observed at various experimental conditions using the normal and steric mode. The ionic strength of carrier, external field strength, species of dispersing agent, and thickness of channel were controllable factors for the particle retention. In the case of low ionic strength of carrier, standard samples showed a lower elution time than that of theoretical value. However, the concentration of dispersing agent was independent of the retention behaviors. The two channels having different thickness, 254 and 76 ㎛, showed relatively similar resolution for polystyrene lattices. In a narrow channel, the separation time was shorter than that in a wide channel, and the lower limit of applicable particle size in steric mode FFF was extended down to 0.9 ㎛.