Parameter optimization for grinding process of micropores with high aspect ratio is discussed in this research. To ensure the surface accuracy on the inner side of deep micropore, the manual polishing or reaming process is a commonly adopted method. However, this process has disadvantages of limitation by operators’ experience and technique, labor consuming, and high cost. Skilled operators are also difficult to train nowadays. In order to address those flaws, this study applied the subtle abrasive jet machining technology and Taguchi Method for experimental design, so as to effectively obtain the appropriate surface roughness and processing uniformity. The Taguchi experimental results showed that when applying a Vacuum Pressure of 60 cmHg and a Air Pressure of 0.5 Mpa, the optimal polishing effect was attained using #2000SiC abrasive particles and an Mix Proportion (SiC: Additive) 2: 1. The average roughness of lifting pin hole was reduced from an original value of Ra 2.39 mm (Rmax: 10.74 mm) to a final value of Ra 0.07 mm (Rmax: 1.10 mm).