AlSi7Cu2Mg was selected as the test substrate, nano TiN particles and sub-micron SiC were used as reinforcement, and the TiN/SiC aluminum composite was prepared by SLM treatment. The microstructure and mechanical properties of the material matrix were analyzed. Results show that a large number of micropores are formed on the surface of AlSi7Cu2Mg sample and the spheroidization of tissue took place. However, 3.5%SiC/AlSi7Cu2Mg and 1.5%TiN/3.5%SiC/AlSi7Cu2Mg form smooth surface structure. It is found that there are four phases of Si, Al, Mg2Si and SiC, and only a small amount of Al4C3 is formed. Fine grains are formed in 1.5%TiN/3.5%SiC/AlSi7Cu2Mg, and obviously different grain orientation and configuration are formed. There are a large number of small equiaxed grains with average size of 4.15 μm and maximum size of 13 μm. The tensile strength and elongation of 1.5%TiN/3.5%SiC/AlSi7Cu2Mg samples are 486 MPa and 9.8%, respectively. Compared with the AlSi7Cu2Mg samples prepared by SLM process, the tensile strength and elongation of 1.5%TiN/3.5%SiC/AlSi7Cu2Mg samples are nearly 20% higher than those prepared by SLM process, and obvious river grain is formed at the fracture site.