Abstract: TiC/Al(7075) composites were fabricated by in situ reaction. The influence of in situ TiC particles form, distribution state and content on the microstructure and mechanical properties of the TiC/Al(7075) compo-sites were discussed. The results show that most spherical in situ TiC particles with aggregate exists in 7075 matrix, the cluster of grain size is about 1 μm. When the mass fraction of in situ TiC particles is less than 6%, the TiC distribution is more uniform. With the increase of in situ TiC particles, the grain sizes of the TiC/Al(7075) composites decrease significantly. But the porosity appear in the microstrcuture when the mass fraction of in situ TiC particles is more than 6%. Hardness and toughness of composite material testing shows that with the increase of the TiC particle concentration, the highest hardness of the surface reaches HB 108, the composites with 6% TiC have the best toughness, the toughness increases by 31.55% compared with the 7075 matrix.