Aiming at grinding quality control problem of the 0.5 mm diameter polycrystalline diamond micro ball-end mill, based on the geometric motion principle of six-axis CNC machine, a mathematical model for the grinding of PCD micro ball-end mill is established, orthogonal experiments are carried out to study the influence of the grinding parameters on the spindle load, the surface roughness of tool rake face, and the radius of micro ball-end mill cutting edge. The results show that the grinding speed has the most significant effect on the surface roughness and spindle load, and the grinding depth has the most significant effect on the radius of the cutting edge. With the optimized process parameters, the diameter error of PCD micro ball-end mill is less than 4.0 μm, the radius of tool blunt circle is 4.5 μm, the angle error of tool is less than 1°. The edge quality is complete without obvious grinding damage defects.