The invention discloses a full-band high-precise aspheric surface 
machining method. The method mainly comprises the following steps: 1) detecting the 
surface shape of a to-be-machined aspheric surface which is formed by milling and 
grinding by using an interferometer; 2) according to the error data of the 
surface shape to be machined, selecting a suitable flexible 
polishing small tool, and determining 
machining parameters of a 
numerical control machine tool by combining a removal function of the small tool; 3) placing an aspheric 
surface element to be machined on a 
machining platform of the 
machine tool, inputting machining parameters, and executing a 
polishing process by adopting a variable step 
pitch spiral machining path; 4) after one-period 
polishing is completed, detecting the 
surface shape of the aspheric 
surface element, and repeating the steps 2, 3 and 4 until the precision of the low-frequency surface shape of the aspheric surface reaches a standard according to the feedback situation of the error data of the surface shape; 5) performing PSD (Power 
Spectral Density) analysis on the surface shape data of the low-frequency surface shape which reaches the standard, selecting a flexible polishing small tool with a large 
diameter according to medium-
high frequency error frequency distribution characteristics determined by a PSD curve, performing fairing process machining on the aspheric surface optical element, and repeating several times until the medium-
high frequency error is controlled effectively. According to the full-band high-precise machining method for the aspheric surface optical element, the full-band high-precise machining of the aspheric surface optical element is completed by only using a CCOS (Computer Controlled Optical Surfacing) 
numerical control small 
grinding head 
machine tool.