Abstract: The present invention discloses a method for preparing 2,3,3,3-tetrafluoropropene using methylmagnesium chloride, comprising the following steps: 1) preparing 1,1,2-trifluoropropene (CH3CF?CF2); 2) preparing 1,1,1,2,2-pentafluoropane (CF3CF2CH3); 3) preparing 2,3,3,3-tetrafluoropropene (CF3CF?CH2). In the present invention, using a Grignard reagent, namely methylmagnesium chloride, and tetrafluoroethylene as starting raw materials, 2,3,3,3-tetrafluoropropene is prepared by three steps of nucleophilic addition-elimination, fluorine addition, and dehydrofluorination in sequence. The process flow is relatively short, and the product yield is high.