Diamond burnishing is an effective finishing process to enhance the surface quality and production rate of machined components. The purpose of this investigation is to select the optimal process parameters, including the spindle speed (S), feed rate (f), and burnishing depth (D) of the hybrid cooling-lubrication system-based diamond burnishing process for decreasing the average roughness (AR) and improving Vickers hardness (VH). The design of experiment entitled Taguchi L16 is applied to perform trials. The principal component analysis (PCA) is employed to compute the weight values of all responses. The combined compromise solution (CCS) is utilized to select the best optimal solution. The results indicated that optimal outcomes of the S, D, and f were 630RPM, 0.10mm, and 0.04mm/rev., respectively. The AR was decreased by 56.0%, while the VH was increased by 16.8% at the optimal solution. The proposed approach comprising the Taguchi, PCA, and CCS could be considered as a powerful technique to solve complex optimizing problems for the diamond burnishing process.