High mechanical properties and anti-oxidation stability of SiC matrix composites are dependent on high performance of CVI-SiC matrix materials.Microstructure and composition of the CVI-SiC matrix materials deposited under different CVI conditions are examined by SEM and XRD.Test results show that crystal orientation of the CVI SiC materials is much dependent on reaction temperature.When it is below 1100℃ the CVI SiC materials have single crystal orientation plane(111),and double crystal orientation planes (111,220) with a small amount of orientation plane(311) when the reaction temperature is above 1100°C.The different stacking modes of SiC crystal grain directly influence the properties of the CVI SiC materials and its composites.Moreover,the properties of the CVI-SiC matrix and composites are influenced by reagent flow.In this work,the effects of the depositing temperature and reagent flow on the properties of the SiC matrix are investigated,and the optimized process is introduced.