The pore size distribution(PSD)measured by the gas bubble point(GBP)method ofceramic microfiltration(MF)membranes prepared by suspension technique was found to be signifi-cantly influenced by the membrane thickness.A culm-like model for pore structure was introduced tocharacterize the membrane pores instead of the conventional model which does not reflect the radiusvariation along the pore passages and is unable to explain the thickness effect on the membrane PSD.A laminate structure,taking the culm-like model for pore structure into consideration,was hypoth-esized for ceramic MF membranes.A mathematical model was then established to quantitativelydescribe the relationship between the membrane number PSD and the membrane thickness.Goodresults were obtained for the correlation of mean pore size and simulation of the PSD for ceramicMF membranes. The pore size distribution (PSD) measured by the gas bubble point (GBP) method of ceramic microfiltration (MF) membranes prepared by suspension technique was found to be signifi-cantly influenced by the membrane thickness. A culm-like model for pore structure was introduced tocharacterize the membrane pores instead of the conventional model which does not reflect the radius variation along the pore passages and is unable to explain the thickness effect on the membrane PSD. A laminate structure, taking the culm-like model for pore structure into consideration, was hypoth -esized for ceramic MF membranes. A mathematical model was then established to quantitativelydescribe the relationship between the membrane number PSD and the membrane thickness. Good results were obtained for the correlation of mean pore size and simulation of the PSD for ceramicMF membranes.