The invention provides a method for preparing oleoyl tributyl citrate plasticizer, comprises: adding citric acid, n-butanol, water-carrying agent and catalytic agent into a reactor, stirring and heating up, controlling the temperature for reaction at 96 degree C until no water is generated again, and obtaining tributyl citrate; adding oleate into the reactor, stirring and heating up, dropping phosphorus trichloride into the reactor, reacting for 3h at 60 degree C, cooling to room temperature, standing for 2h, and separating to obtain; and a step 3, synthesizing oleoyl tributyl citrate; adding tributyl citrate and a catalytic agent into the reactor, stirring and heating up to 70 degree C, dropping oleoyl chloride, absorbing the generated hydrogen chloride by introducing the drier into base, stopping the reaction until the pH value of base has no change, and obtaining oleoyl tributyl citrate by neutralizing with sodium carbonate solution, water washing, and vacuum filtrating.