Abstract: In order to improve the shape accuracy of axisymmetric aspheric lens and reduce its finishing cost, the K9 optical glass was milled with a small diamond grinding head under different processing parameters and NC tool path conditions. The profile accuracy of the lens is measured by a three-coordinate measuring machine. The normal profile error of the aspheric lens is calculated by measuring data points, and is compensated by NC machining of the effective cutting radius of the grinding head.The experimental results show that when the NC tool path is parallel finishing and contour finishing,the maximum profile deviation PV and the mean error RMS are 54.48 and 22.88 μm, 98.46 and 28.88 μm, respectively.The surface accuracy of aspheric lens can be improved by optimizing the effective cutting radius of diamond grinding head. The optimized PV and RMS values of aspheric lens profile accuracy after parallel finishing are 44.52 and 7.37 μm, respectively.