The invention belongs to the technical field of textile printing and dyeing, and particularly relates to a high-whiteness pure cotton fabric processing technology which comprises a whitening process. The whitening process comprises the following steps: conducting padding on a pure cotton fabric by use of a whitening liquid, carrying out steaming in a steaming box fully filled with saturated steam, and then carrying out water washing, neutralization and drying, wherein the pH value of the dried pure cotton fabric is controlled to be 6-7.5. According to the processing technology, padding by the whitening liquid, steaming, water washing, drying are conducted on the pure cotton fabric which is subjected to singeing, desizing, scouring, oxygen bleaching and mercerization, and then tentering and pre-shrinking are carried out; in the oxygen bleaching process, H2O2 is utilized for bleaching, and meanwhile organic peracid is added; a brightening agent with a medium or relatively high affinity is selected as the whitening liquid; after the pure cotton fabric is subjected to padding by the whitening liquid, the pure cotton fabric subjected to padding enters the guide roller type steaming box fully filled with the saturated steam for steaming, and then water washing, neutralization and drying are carried out; after the pure cotton fabric is treated according to the processing technology, the whiteness of the pure cotton fabric is improved to 155 or above, and the whitened pure cotton fabric is bright in color and has the soaping fastness of four-level or above.