Abstract: The reheated microstructures and influencing factors of semi-solid ingots of 4.4% TiC_p/7075 composites were investigated by SEM, TEM and DSC. The results show that the optimal remehed parameters of 4.4% TiC_p/7075 composites are the remolded temperature of 590 to 610℃ and the holding time of 10 to 20 min. 4.4% TiC_p/7075 composites are of high stability during the remelting process and the size of spherical grains can hardly increase with the increase of temperature and holding time. The coarsening velocity of grains in 4.4% TiC_p/7075 is 118.96μm³·s^-1, which is less than 311.7 μm³· s^-1 for 7075 matrix alloy, and more suitable for semi-solid thixoforming.