Considering the structural characteristics of fibers, the arrangement of fibers and the number of layers of fibers, the micro-size model of pleated fibers filter media was established based on the control program written by MATLAB, and its solid volume fraction (?) of pleated fibers filter media was calculated. The mathematical correlation between filtration velocity (v) and pressure loss (Δp) of micro-size model was obtained by numerical simulation, and then the viscous drag coefficient (C1) was solved. Based on the above work, a macro-size model of pleated fiber filter media was established, and based on ? and C1 obtained by the micro-size simulation, the mathematical correlation between the face velocity (u) and Δp at macro-size was solved by numerical simulation method, and the mathematical correlation were compared with several empirical formulas. The results showed that the arrangement of the fibers and the thickness of the pleated fiber filter media had an effect on Δp, but had little effect on C1 and other properties. In addition, the properties of pleated fiber filter media obtained at micro-size can provide guidance for macro-size research, and the property parameters of macrostructure can be obtained by using the data obtained from the microstructures. The research results of this study had important theoretical and practical significance for expanding the research methods of fiber filter media and optimizing its structure.