To improve the surface forming quality and machining efficiency of aluminum matrix composites, a twodimensional ultrasonic combined electrolysis/discharge generating machining technology (2UE/DM) with low voltage and low current density was proposed. Using the side of a tool coated with diamond grains, three different processing contrast tests and performance tests under three sets of parameters were carried out on the composite. The current, material removal rate (MRR) and surface roughness of SiC_pAl composites processed in 0.5% NaNO₃ (mass fraction) solution were measured, and the effects of tool rotation speed, voltage and amplitude on processing efficiency and quality were explored. The results showed that the vibration of the workpiece periodically changed the machining gap, and the discharge frequency increased by 2 times per vibration period. At 5000 r/min, the discharge frequency decreased, the surface roughness decreased by 13.2% compared with 1000 r/min. At the voltage of 6 V, the material removal rate reached 0.89 mm³/min, which was 45.9% higher than 3 V, but more reinforcing particles were exposed at the higher voltage, and the surface roughness was 1.4 μm higher than 3 V. When the amplitude increases to 5 μm, the surface roughness was 17.5% lower than 2 μm, and the technology had higher machining quality.