A sequential modelling approach consisting of passing information across length scales is presented to simulate macroscopic behavior of composite materials. The modeling procedure utilizes a proper flow of information from molecular scale to macroscopic scale including material characteristics at different length scales. Both molecular dynamics and analytical/numerical methods were used in the multiscale analysis together with some experimental observations obtained from Raman micro-spectroscopy and X-ray microtomography. The multiscale procedure is systematically applied to short glass fibre polypropylene composite material.