The invention discloses a preparation method and application of a metal organic frame material. The preparation method comprises the steps: adding nickel nitrate hexahydrate, 4,4'-bipyridine and 4-(5-tetrazolyl)-benzoic acid into a mixed solvent composed of N,N-dimethylformamide, ethanol, water and hydrofluoric acid, and then, carrying out uniform stirring to obtain a mixed solution, wherein the mixed solvent comprises water, ethanol, N,N-dimethylformamide and hydrofluoric acid; placing the obtained mixed solution into a sealed high-pressure reactor, heating the mixed solution to 110-120 DEG C, preserving the heat for 65-85h, and then, cooling the mixed solution to the room temperature at the speed of 0.1-0.2 DEG C/min to obtain a reaction product; filtering the obtained reaction product to obtain a green bulk crystal; and exchanging the obtained green bulk crystal with methanol for 48-96h, and then, carrying out vacuum heating at 180 DEG C for 4-8h to obtain the metal organic frame material. The metal organic frame material is used for realizing selective adsorptive separation of C2H4 in the mixed gas of C2H4 and CH4.