The invention relates to a preparation device and a preparation method for 2,3,3,3-tetrafluoropropene and belongs to the technical field of fluorochemical industry. The preparation device for 2,3,3,3-tetrafluoropropene is simple in structure, easy to operate, low in energy consumption and suitable for industrial production. According to the preparation method for 2,3,3,3-tetrafluoropropene, 1,1,1,2,3-pentachloropropane or 1,1,2,3-tetrachloropropene and hydrogen fluoride are taken as raw materials, any one or a combination of tin tetrachloride, stannous fluoride, antimony chloride, titanium tetrachloride, titanium fluoride, aluminium chloride and aluminum fluoride is taken as a catalyst, and 2,3,3,3-tetrafluoropropene is synthesized with a one-step liquid phase method with high catalyst contact rate. The process is simple, and the technological flow is simplified greatly; equipment investment is reduced remarkably due to less equipment, and 99.9% 2,3,3,3-tetrafluoropropene can be obtained. The product selectivity is high, reaction is completed by one step, the flow is short, the conversion rate is high, few byproducts are produced, and energy consumption is low.