the present invention provides a process for producing 2 , 3 , 3 , 3 - tetrafluoropropene including the step of dehydrofluorinating 1 , 1 , 1 , 2 , 3 - pentafluoropropane , wherein 1 , 3 , 3 , 3 - tetrafluoropropene and 1 , 1 , 3 , 3 , 3 - pentafluoropropane are supplied together with 1 , 1 , 1 , 2 , 3 - pentafluoropropane to a reactor containing a catalyst to simultaneously perform dehydrofluorination reaction and isomerization reaction . according to the process of the present invention , 2 , 3 , 3 , 3 - tetrafluoropropene can be efficiently produced by effectively using the by - products of the dehydrofluorination reaction .