Disclosed is a mass transfer vessel or a mass transfer tower, which is installed in water purification equipment, condensate water demineralization equipment, sewage treatment equipment, waste water treatment equipment, or chemical reactors to perform filtration, adsorption, ion exchange, regeneration of an ion exchange resin, chemical reaction, and spray of a chemical cleaning solution, and more particularly to a method for designing radial distributors in a mass transfer vessel, which uniformly distribute influent flow quantity into all cross sections so as to improve the efficiency of a mass transfer process, such as filtration, adsorption, ion exchange, a chemical reaction process, and a chemical cleaning process.