The invention provides a method for preparing triphenylphosphine in a reducing manner. Phenylphosphonicdichloride or chlorodiphenylphosphine is used as a reducing agent, and raw materials are low in price and easily obtained; under the effect of a catalyst, the phenylphosphonicdichloride or chlorodiphenylphosphine and triphenylphosphine oxide are subjected to reducing reaction, stabilities of phosphine oxygen double bonds in the triphenylphosphine oxide and oxidation products (phenylphosphonic dichloride or diphenylphosphinyl chloride) of a reducing agent are different, the stabilities of thedouble bonds of the phenylphosphonic dichloride and the diphenylphosphinyl chloride are good, the double bonds of the triphenylphosphine oxide are broken under the effect of the catalyst, the double bonds of the formed phenylphosphonic dichloride and the formed diphenylphosphinyl chloride are not easily damaged by the catalyst, and therefore, triphenylphosphine can be obtained under gentle conditions; the oxidation products (the phenylphosphonic dichloride or the diphenylphosphinyl chloride) of the reducing agent are important organic synthesis intermediate (such as synthesis of organic phosphate); and moreover, the amount of the catalyst required in the method is small, and the catalysis efficiency is high.