The operation range of the pressure drop between the peak and the base line during the pulse-jet cleaning of a ceramic filter relates closely with the grouping number of the filter elements in the filter unit, as well as the design and the operation conditions of the pulse cleaning system. A semi-empirical model was developed to predict the pressure drop of the filter unit versus the operation time according to the grouping numbers of the total filter elements in this study. The model is based on theoretical considerations and the application of the experimental data to develop a simple equation, which should be useful for preliminary design and operational inspection. The semi-empirical formula predicts the operational values of the pressure drop between the peak and the base line, which suggests the guideline for grouping of the filter elements for the pulse-jet cleaning. Peak pressure drop decreases gradually and then finally approaches a minimum stable value as the number of the cleaning group increases. Otherwise, the base line pressure drop increases gradually and then finally approaches a maximum stable value as the number of the cleaning group increases. Thus, the gaps between the peak and the base line pressure drop become narrow as the number of cleaning group increases. This phenomenon of gap reduction is desirable for the pulse cleaning of the filter element as it reduces the pulse cleaning load. Moreover, pulse cleaning becomes more effective as the number of the cleaning groups increases.