The rheology of Linear Low Density Polyethylene (LLDPE) concentrated suspensions containing two different particle size (nano and micro size) of natural calcium carbonate (CaCO3), at various loading were studied using the Dynamic Mechanical Rheometer. The combination of particles, ratio of particle size, mixing ratio, particle-particle and particle-polymer interactions on the rheological behavior was investigated. Generally, highly loaded suspensions can be observed unique behavior. Shear thinning was observed for most suspension, whilst shear thickening was obtained for highly concentrated suspensions. In particulate the composition of compounds, both behaviors were observed. Therefore, it leads a better uniformity of the particles in suspension. Since characterized the best examples of dispersion and distribution CaCO3 in matrix, stretching porous films containing fillers were prepared for them. Morphology, microstructure and pore examined using Scanning Electron Microscopy (SEM) were studied. Using the standard of Water Vapor Transmission Rate (WVTR) was measured and compared with the sample used in the market. Taking advantage of the bimodal suspensions was improved rheological behavior, and the process is more suitable properties, and finally achieved to the final properties more desirable. Keywords: highly concentrated suspension, bimodal suspension, rheology, morphology, polyoethylene, nano and micro size of CaCO3, WVTR , porous film.