Aluminum matrix composites (SiC_p /Al) exhibit superior specific strength, excellent wear resistance, good thermal stability, and tunable properties, and thus have become key structural materials in high-tech fields including aerospace and rail transit. However, the presence of high-hardness particle reinforcement phases poses severe challenges to machining tools. Aiming at the demand for efficient machining of SiC_p /Al composites, this study systematically compared the performance differences between two superhard tools (PCD and PCBN) under varying cutting parameters by dynamically monitoring process parameters (e.g., cutting force and cutting temperature) and conducting correlation analysis of tool life and wear morphology, the cutting stability and failure mechanisms of the two tool types were comprehensively evaluated. The results show that PCD tools yield lower cutting forces and temperatures under different cutting speeds and high feed conditions due to their high thermal conductivity and low friction characteristics; Under the high-efficiency cutting process parameters (cutting speed v_c = 250 m/min, feed per tooth f_z = 0.1 mm/z), when the cutting distance reaches 2100 mm, the wear amount of the PCD tool is significantly lower than that of the PCBN tool, and its wear resistance is relatively improved by 61.80%. The dominant wear mechanisms differ between the two: PCBN tools are dominated by abrasive wear, random brittle spalling and diffusion wear, while PCD tools are characterized by adhesive wear and uniform micro-chipping with less severe abrasive wear. This study provides a theoretical and practical basis for optimizing the efficient and precision machining processes of SiC_p /Al composites.