304 Stainless Steel Dutch Mesh are high quality filter media with high mechanical strength and micro-aperture. However, because of their high flow resistance due to their complex flow paths, it is critical to predict the pressure drop with high precision for the filtration process. Therefore, we studied the effect of the pore structure of the 304 Stainless Steel Dutch Mesh on the flow resistance. First, we propose a computational model for estimating the pore size of a twill weave grid to thoroughly understand the pore structure; however, the pore structure of a common 304 Stainless Steel Dutch Mesh has been clarified. Next, numerical simulations were performed using a combination of lattice Boltzmann and immersion boundary methods. It was found that the resistance of the 304 Stainless Steel Dutch Mesh increased at the inner hole where the volume fraction increased, and in the twill Dutch woven mesh, the resistance of the center also changed with the local twist of the low path. Based on these findings, we derive an equation for estimating the pressure drop of the Dutch weaving grid and verify its effectiveness through experiments. This makes it possible to predict the pressure drop reasonably and highly accurately.