A ceramic membrane was generally regarded as a black box, which was useless to explain the essential mechanism of the membrane process. The Cannan-Kozeny (C-K) and Hagen-Poiseuille (H-P) equations were improved to predict water permeability of ceramic membranes. Therefore, the effects of microstructure parameters (pore size, thickness and porosity) of ceramic membranes on pure water flux were quantified. The water permeability experiments showed good correspondence with the improved C-K equation assuming that the membrane layer had accumulated particles. This work provides a new method to understand the separation mechanism of ceramic membranes and was also useful for preparing ceramic membranes with good performance. This work may build a bridge between the filtration process and microstructure parameters of membranes.