TiCp/ZA-12 composites have been fabricated by XDTM method and stirring-casting techniques. Microstructure of the composites has been studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that TiC particles distribute uniformly in ZA-12 matrix alloy. The interface between reinforcements and matrix alloy is very clean, and there is not interface reaction between TiC particles and ZA-12 matrix alloy. The tests for mechanical properties reveal that the tensile strength, yield strength, elastic modulus and hardness of the composites are improved obviously due to the incorporation of TiC particles. The strengthening mechanisms are attributed to the following factors: dispersion strengthening of TiC particles, grain refinement of ZA-12 matrix alloy and high-density dislocations existing in ZA-12 alloy.