The stainless steel is machined with the picosecond laser, and the morphologyandquality are characterizedby theconfocal microscopy. The effect of laser fluence and feeding speed on the morphologyandquality of micro-holes, and the effect of angle between laser beam and workpiece on taper are studied. The results show that the heat effect and diameter of micro-holes are increasing, and the taper and the circularity at entrance are decreasing as the increasing of the laser fluence. The circularity at exit increases as the laser fluencegrows, then it tends to be stable till the decreasing. The circularity at entrance keeping on 98% and the diameter at entrance aren’t affected by the feeding speed. The diameterat exit decreases as the feeding speed grows, then it tends to be stable.When the feeding speed increases, the conicity increases to 4°, the circularity at exit increases to 97%～98%. At last, the nonlinear correlation between actual conicity and rotation angle of workpiece is demonstrated, and the function is given.