The morphological structure of silicon aluminium carbons(SAC)was studied by transmission electron microscope and X-ray diffraction. The law of ef- fect of such factors as graininess

compounding and surface activity on mechnical properties of SAC/HDPE system was studied by orthogonal experiment.The re-sults show that the structure properties of SAC is lower.It is a collection of irregu- iar particles.In SAC exists a -SiO2 structure

which has a certain surface activity and it has strengthening action. The mechanical properties of test sample of sheet materials made with SAC of 320 bores and by 25% of HDPE mass was obviously improved.