The invention relates to a film falling type distributor. The two sides of a sulfonic acid inlet pipe are connected with a cone through fixed angle iron, wherein the cone is located below the sulfonicacid inlet pipe. The center of the upper end of the cone is connected with a lower end opening of the sulfonic acid inlet pipe through linkage angle iron, and two circulating areas are formed by thecone, the fixed angle iron, the linkage angle iron and the lower end of the sulfonic acid inlet pipe. A cone located in a containing groove of a first-stage distribution disc is arranged in the first-stage distribution disc. The first-stage distribution disc, a second-stage distribution disc and a third-stage distribution disc are distributed in parallel up and down and are connected through connecting angle iron. The two sides of the lower end of the third-stage distribution disc are connected with the inner wall of an upper pipe box barrel section through third-stage angle iron. The diameterof the first-stage distribution disc, the diameter of the second-stage distribution disc and the diameter of the third-stage distribution disc are sequentially increased, and multiple circulating holes are formed in each of the first-stage distribution disc, the second-stage distribution disc and the third-stage distribution disc. In the film falling type distributor, sulfonic acid firstly flowsinto the first-stage distribution disc through the two circulating areas and then sequentially impacts on the three distribution discs, the flow speed is reduced, distribution is achieved again layerby layer, and therefore dead zones and liquid-free zones are eliminated, and the sulfonic acid can be evenly distributed on a heat exchange pipe.