The invention discloses a method for synthesizing trans-1,3,3,3-tetrafluoropropylene. The method is characterized in that 1,1,1,3,3-perfluoropropane generates dehydrofluorination reaction to synthesize the trans-1,3,3,3-tetrafluoropropylene in the presence of alkali metal fluoride and an aprotic polar solvent, wherein a reaction temperature is 50-180 DEG C, and reaction time is 0.5-24 hours; the alkali metal fluoride is potassium fluoride or cesium fluoride; and the aprotic polar solvent is of an ester type, a nitrile type, a ketone type, an amide type or a sulfoxide type. The method for synthesizing trans-1,3,3,3-tetrafluoropropylene provided by the invention has the advantage of being environmental-friendly.