The invention relates to a method for producing beta-high-purity gypsum powder by using phosphogypsum. The method comprises the following steps: (1) drying phosphogypsum until the mass content of free water is less than or equal to 3%, and calcining at a temperature of 130 to 150 DEG C under pressure of 99.0KPa to 100. 2KPa for 2.5 to 3.5 hours; (2) crushing a material calcined in the step (1) until the particle size is less than or equal to 125 microns and the screen residue is less than or equal to 3.00%; (3) hermetically aging the material obtained in the step (2) at normal temperature for 3 to 5 days, crushing the aged material to different grades of particle size between 75 to 125 microns, and carrying out graded mixing on products of different particle sizes to obtain beta-high-purity gypsum powder. The calcination is carried out under the negative pressure condition of 99.0KPa to 100. 2KPa, the energy consumption is low, and the obtained product has high performance index, strong stability and high performance cost ratio; the whiteness is more than or equal to 94, the content of calcium sulfate hemihydrate is more than or equal to 92%, the radioactivity index is low, and the wet flexural strength is up to 4.0Mpa at 2 hours.