Polishing process is the final step for the fabrication of optical surfaces. This paper presents a theoretical and experimental investigation on the removal of material from a surface during the polishing process. The model in this paper assumes that the material removal rate follows Preston equation and the pressure distribution at the contact area is Hertzian. Particularly, the effect of the tool posture, which is described by the inclination angle and declination angle, upon the local material removal profile is modeled and analyzed. On the basis of the analysis, a novel method is proposed to optimize the tool angles. A series of polishing experiments were conducted to verify the effectiveness of the proposed model. The theoretical and experimental results indicate that (1) the inclination angle has large effect on the local removal depth, and (2) the location of the maximum removal depth bias away from the center of the profile and the direction of this bias is determined by the declination angle. The model in this paper is potentially useful for the planning of the polishing posture and the tool path during the polishing process.