The invention discloses a flat-top 
light beam shaping control method for achieving an abrupt edge and low light-intensity variation and a shaping device thereof, and the flat-top 
light beam shaping control method and the shaping device relate to a flat-top 
light beam shaping device for achieving the abrupt edge and the low light-intensity variation, and further relate to a shaping control method, so as to solve the problems in the prior art that a position cannot be flexibly set to shape a light beam, the shape and the 
caliber of the shaped light beam cannot be changed flexibly, the edge is not abrupt, and further, the flat top light-intensity variation of the light beam is large. A lens in the shaping device provided by the invention is positioned between a surface where an optical phase array is positioned and an output surface; the light beam passes through the optical phase array, and then goes through a 
Fourier transform lens, so that the light beam is shaped; a 
light field is obtained at the output surface; and an intensity distribution collecting module collects the intensity distribution of the light beam of the shaped 
light field of the output surface and outputs the intensity distribution of the light beam to a processor module, and judges whether to adjust the phase of the optical phase array or not through calculating an RMSE (root-mean-
square error ) value. By using the device provided by the invention, the anticipative shaping of the light beam is achieved by the shaping control method. The flat-top light 
beam shaping control method and the shaping device are applied to the technical field of 
diffraction optics and 
laser shaping.