FEM calculation for the preparation process of SiC fiber and SiC/Ti-6Al-4V composite was carried out to investigate the effect of different processing parameters on the residual stress of the SiC fiber as well as the densification behavior and residual stress of the composite. The results show that, for the fabrication process of fibers, the axial thermal stress of the WC layer decreases with the decrease of deposition temperature and thickness of C layer. For the densification of composites, HIP temperature and sheath thickness have greater impact on the density, but HIP time and fiber volume fraction have smaller impact; with the increasing HIP temperature and decreasing sheath thickness, the density of the composite could be enhanced; the radial residual stress on the matrix greatly increases with the increase of HIP temperature and fiber volume fraction and decrease of sheath thickness appropriately; the hoop residual stress on the matrix greatly decreases with the increase of HIP temperature and sheath thickness, while decrease of HIP time appropriately. Finally the following processing parameters were recommended for preparation of SiC/Ti-6Al-4V composite with good quality: HIP temperature 950-960℃, HIP time 9 h and sheath thickness 70-80 mm and fiber volume fraction 45%-50%. FEM calculation results show some differences with those measured in the experiment for the residual stress of the composite, but with similar variation tendency.