High-entropy alloy (HEA), as a class of new alloy materials characterized by high stability, excellent specific strength and corrosion resistance, have attracted much attention in the field of aluminum matrix composites (AMCs). To study the effect on microstructure and mechanical properties of aluminum alloys, HEA (AlCoCrFeNi) particles reinforced ADC12 composites were successfully fabricated by using high energy ultrasonic casting process in this study. Subsequently, the effect of HEAs addition on the microstructure and mechanical properties of ADC12 alloys was systematically investigated. Results showed that the added HEA particles were tightly bonded to the aluminum matrix. The Al2Cu phase in the matrix was refined. Meanwhile, the tensile strength and microhardness of the alloys with the addition of HEA particles were significantly improved. The as-prepared composites with 12 wt. % HEAs exhibited yield strength (YS) and ultimate tensile strength (UTS) increased by 16.9% and 21.9% compared to these of the matrix, respectively. The wear rate of the composites was also decreased due to the enhancement of microhardness in 20 N applied load. It was mainly attributed to the load transfer strengthening, dislocation proliferation and the optimization of the microstructure.