The invention discloses a technology for continuously producing high-purity oxygen by water electrolysis, which utilizes soft water deprived of dissolved air as a raw material, and finally obtains a high-purity oxygen product conforming to the national standard GB/T 14599 by electrolysis, catalytic dehydrogenation and adsorption dewatering. The main steps are as follows: (1) the deprivation of the dissolved air in water: a small amount of oxygen is adopted to carry out counter-current bubbling back blowing to the raw material water so as to deprive the nitrogen and other dissolved gases dissolved in water; (2) water electrolysis: an industrial electrolysis unit is used for electrolyzing the nitrogen-deprived soft water, and industrial electrolysis oxygen is obtained from the anode of an electrobath; (3) catalytic dehydrogenation: Pd or Pt is taken as a catalyst, and the H and O in oxygen are electrolyzed to react and generate water; and (4) dewatering and drying: the molecular sieve constant pressure temperature swing adsorption technology is adopted to deprive the water in oxygen so as to obtain high-purity oxygen. The technology is the improvement of the existing industrial oxygen producing technology by electrolysis, and can continuously produce high-purity oxygen, with the advantages of low investment, no environment pollution and high hydrogen recovery rate.