The invention discloses a preparation method of an Ni1-xFexOOH-modified titanium dioxide photoelectrode. The preparation method comprises the following steps that a titanium source compound is added to hydrochloric acid and stirred, then conductive glass is inserted into the mixture, a hydrothermal reaction is generated, TiO2 grows to the surface of the conductive glass, the conductive glass is taken out, washing, drying and calcining are conducted, and the TiO2 photocathode is obtained; and then the TiO2 photocathode is used as a working electrode, an aqueous solution containing ferric chloride, nickel chloride, sodium fluoride, potassium chloride and hydrogen peroxide is used as electrolyte, Ni1-xFexOOH is modified on the working electrolyte through cyclic voltammetry, washing and drying are conducted, and the Ni1-xFexOOH-modified titanium dioxide photoelectrode is obtained. The prepared photoelectrode is used for hydrogen production through photoelectrocatalysis and water of decomposition, carrier recombination of the TiO2 photoelectrode can be inhibited effectively, besides the reaction activation energy is facilitated, and a surface oxygen evolution reaction of the photoelectrode is promoted.