1. A method for calibrating a spot color, comprising: determining a target value for the spot color; and calibrating a printing device in an enumeration cycling manner, so that a spot color measurement value of a color block output by the printing device approximates the target value, wherein the calibrating further comprises: 1) setting the target value as a spot color standard value; 2) setting a plurality of spot color values centered at the spot color standard value, the spot color standard value and the plurality of spot color values constituting a set of spot color enumeration values; 3) printing, by the printing device, a color target chart by using the spot color enumeration values; 4) measuring each color block on the color target chart to obtain a spot color measurement value of the each color block; 5) determining a chromatic aberration between the spot color standard value and each obtained spot color measurement value; 6) determining the spot color enumeration value of the color block corresponding to the spot color measurement value having a minimum chromatic aberration; 7) setting the determined spot color enumeration value which is corrected by a set amplitude as a new spot color standard value; 8) repeating steps 2 to 7 until a minimal value of the chromatic aberrations begins to rebound, then stopping the repeating and determining the spot color enumeration value of the color block corresponding to the spot color measurement value having a minimum chromatic aberration as a final print value.