Pleated filter panels have been used in a variety of filtration applications in industries, office building and residential houses. In addition to the property of filtration media, the performance of clean pleated filter panels is in general influenced by pleating parameters such as the pleat count, pleat height, and pleat shape. Work has been conducted to study and optimize the pressure drop of clean pleated filter panels. General correlation curves were obtained for pleated panels with rectangular and triangular pleat shapes, which have been used in filtration industry for the design of clean pleated filter. However, the systematic study on the optimization of pleated filter panels under the particle loading condition has been scattered in the literaure. In this study, a detailed numerical model was constructed to predict the pressure drop of pleated filter panels under the dynamic particle filtration process. In this model, the flow field was modeled by Navier-Stpkes equations for flow region outside filtration media and modified Navier-Stokes equations for the flow in media. The flow governing equatiosn were solved via the use of COMSOL Multiphysics software. To model the particle filtration, the particle deposition in filter media was predicted by particle tracing method via solving the Langevin equation with Matlab. The change and optimization of pleated filter pressure drop as the function of the filtration media and pleating configuration as well as the evolution of medium characteristics under the particle loading were systematically investigated in this study. The detail of study result will be presented in this talk.