The permeate flux of fully retentive dead-end ultrafiltration has been monitored with progress of filtration time, so as to understand a membrane fouling mechanism due to the consistent formation of cake layer. We selceted the polystyene latex with negatively charged surfaces as well as the flat membrane having asymmetric pores as a model colloid and a model membrane, respectively, and their zeta potentials incorporated wih a physicochemical interaction betweem particle and membrane surface were characterized. As the transmembrane pressure difference(i.e.,Δp) increases, the permeate flux increases, while it shows a decreasing behavior with the increase of solution ionic strength. Note that the effect of solution ionic strength on the permeate flus is found to increase, as Δp decreases. When Δp is 4 psi, the permeate flux at KCI 100 mM decreased by about 16% compared to the flux at KCI 0.01 mM. It is obvious that, as the solution ionic strength decreases, the estimated specific cake resistance decreases, but the cake compressibility increases. This phenomena allow us to analyze the long-range electrostatic interaction between pairs of suspended latexparticles, in which the expanded double layer around particel surfaces due to a decreasing solution ionic stength provides the development of loosely packed cake layer during the membrane filtration.