The invention relates to the optical field, provides a fused quartz continuous phase plate laser preparation method, and is used for acquiring the smaller removal function size to meet the more refined requirement of focal spot uniformity control. The technical scheme can be summarized as follows: firstly laser beams are focused, then the laser output power parameters and the scanning vibrating mirror scanning speed are set and the scanning vibrating mirror scanning path parameters are set, then a fused quartz element is arranged at the focus of the laser beams, the surface of the fused quartz element is irradiated by laser to change hypothetical temperature distribution of the scanning area of the fused quartz element to be corresponding to the set continuous phase plate space structure so as to obtain a laser irradiation element, and finally the laser irradiation element is etched through the mega-sonic assisted hydrofluoric acid etching technology and the laser irradiation element is enabled to present the hypothetical temperature regulation and control area contour and thus the fused quartz continuous phase plates can be obtained. The beneficial effects of the fused quartz continuous phase plate laser preparation method are that the processing efficiency can be enhanced and the method is suitable for processing the fused quartz continuous phase plates.