An interior progressive addition lense (PAL) numerical control (NC) lathe system was designed. A double-CPU structure and a voice coil motor were used to realize high-precision lathe machining. By adjusting the proportion-integral-differential (PID) parameter for all the three-axis motor,taking the closed-loop control technique and error compensation,we limit the positioning accuracy to 1 m and the repetitive positioning accuracy to 2 m. The shaping method of the interior PAL with NC turning was studied,and the lens profile was divided into four regions,near vision,far vision,astigmatism and gradation. The corresponding mathematical expressions were proposed. Based on these,we developed an interior PAL′s profile data processing software,realized the interior PAL profile software off-line interpolation,and provided cutting tool control data for the mirror surface processing.