The invention provides a hydroxylamine potassium disulfonate preparation method and a hydroxylamine disulfonic acid radical ion concentration calibration method. The preparation method is characterized by including steps: step 1, weighing potassium nitrite and potassium acetate, dissolving potassium nitrite and potassium acetate into ice water, pouring into a reaction absorption tower, and addingice blocks to obtain mixed solution; step 2, adding sodium hydrogen sulfite crystals into a reactor, adding deionized water, and performing water-bath heating to generate SO2 gas; step 3, feeding SO2gas into the reaction absorption tower, arranging the reaction absorption tower on a magnetic stirring machine for stirring, and after excessive SO2 gas enters a tail gas treatment device through a suck-back prevention device and generates bubbles in the tail gas treatment device, putting the reaction absorption tower in a refrigeration chamber to obtain crystals at the bottom of the reaction absorption tower; step 4, washing the crystals with ice water, and drying to obtain hydroxylamine potassium disulfonate. According to the calibration method, the hydroxylamine disulfonic acid radical ionconcentration is calibrated through an ultraviolet spectrophotometer and a Raman spectrometer.