In order to study the rotation and the fracture failure of SiC particles during backward extrusion process of 7075/SiCp composites prepared by spray deposition，the Deform-2D finite element simulation was applied in the extrusion temperature range of 300~450 ℃, extrusion ratio range of 4~64 and extrusion speed range of 2~30 mm/s. The results showed that the rotation of SiC particles was caused by the uneven flow of the matrix alloy in the process of backward extrusion. The farther away from the central axis, the greater the flow inhomogeneity and the rotation tendency of SiC particles, and the degree of flow inhomogeneity increased with the increase of extrusion speed and extrusion ratio. During the process of backward extrusion, the fracture failure might occur under large stress if the SiC particles were not coordinated with the matrix movement, and higher fracture failure fraction occured in the outerlayer. The fracture failure of SiC particles could be avoided to the utmost extent at extrusion ratio of 4~25 and extrusion temperature of 400-450 ℃. Under the extrusion ratio of 16, the advisable extruding speed should be controlled in the range of t=400 ℃、v<30 mm/s，t=425 ℃、v<20 mm/s and t=450 ℃、v<5 mm/s