ZA27 alloy-based composites reinforced by 10–40 vol. % Ti3AlC2 particles in a step of 10 vol. % were prepared by pressurelessly sintering mechanical alloyed powders at 870 °C for 2.5 h. The effects of Ti3AlC2 content on hardness, density, stretching and bending performance were studied. The results demonstrate that a well bonded interface could be obtained by weak reaction occurred at the interface between Ti3AlC2 and ZA27 alloy during sintering process, and which is beneficial to the mechanical properties of the Ti3AlC2 /ZA27 composites. An increase in Ti3AlC2 content (up to 30 vol. %) leads to enhanced hardness and mechanical strength of the composites due to dispersion strengthening of nano-sized Ti3AlC2 particle. However, with an increase in Ti3AlC2 content to 40 vol. %, the hardness and strength decrease because of the growing number of pores. Comparing the four composites with different Ti3AlC2 contents, the 30Ti3AlC2 /ZA27 composite possesses the best properties of 310 MPa for tensile strength, 528 MPa for bending strength and 1.24 GPa for Vickers hardness. Besides the good interfacial bonding, the improved mechanical properties of the Ti3AlC2 /ZA27 composites are also attributed to the fine-grained microstructure and well dispersed reinforcements.