Abstract: Unilateral compression tests on spray formed 7075+TiC Al alloy at semi-solid state were carried out using a Gleeble-1500 dynamic material testing machine. The microstructures of vertical and cross sections of the specimens after deformation were observed by SEM, and the grain size was measured by a mean linear intercept method. The relationship between the deformation temperature and grain size was analyzed. The results indicated that the grain size increased with the increase of deformation temperature and distributed in 10-21 μm at 580-620℃. When the deformation temperature was up to 610℃ with a deformation rate of 1 s^-1, the alloy revealed advantageous thixoforming performance.