NOVELTY - A coke oven gas methanation catalyst is prepared by (A) selecting chemical substance materials (B), grinding and sieving, (C) performing solid mixing, (D) heating and decomposing via microwave, (E) cooling, (F) opening furnace to fetch the product, (G) detecting, assaying, analyzing and characterizing, and (H) storing product. The substance materials comprise alumina, nickel nitrate hexahydrate, cerous nitrate hexahydrate, and silicon carbide. The step (F) comprises stopping external water cooling, removing quartz crucible, and obtaining fine catalyst powder.    USE - Method for preparation of catalyst for gas methanation of coke oven (claimed).    ADVANTAGE - The method has advanced technique, short flow, convenient operation, short preparation time, low energy consumption, rational material proportion, detailed and accurate data, and good product stability. It is capable of meeting need of methanation of the gas of coke oven under condition of filling carbon dioxide.    DETAILED DESCRIPTION - Coke oven gas methanation catalyst is prepared by (A) selecting chemical substance materials (B), grinding and sieving, (C) performing solid mixing, (D) heating and decomposing via microwave, (E) cooling, (F) opening furnace to fetch the product, (G) detecting, assaying, analyzing and characterizing, and (H) storing product. The step (A) comprises performing quality purity control to substance materials. The substance materials comprise 99.5% gamma -alumina ( gamma -Al2O3) (6 plus minus 0.01 g); 98.5% nickel nitrate hexahydrate (Ni(NO3)2.6H2O) (7.80 plus minus 0.01 g); 98.5% cerous nitrate hexahydrate (Ce(NO3)3.6H2O) (1.3 plus minus 0.01 g); 99.5% silicon carbide (SiC) (1.50 plus minus 0.01 g); 90% cooling water (H2O) (50000 plus minus 100 mL); and 99.9% nitrogen (N2) (50000 plus minus 100 cm3). The step (B) comprises respectively grinding gamma -Al2O3 and SiC via agate mortar and sieving obtained product via a 100 mesh sieve to obtain fine powder, where particle diameter of fine powder is not more than 0.15 mm. The step (C) placing ground and sieved fine powder in agate mortar, grinding and mixing according to the mass ratio of gamma -Al2O3, Ni(NO3)2.6H2O, Ce(NO3)3.6H2O and SiC of 60:78:13:15 to obtain solid mixed fine powder which is placed in a quartz crucible. The step (D) is performed in microwave radiation heating furnace, where step is finished by heating, vacuuming, nitrogen protecting, external water circulating and cooling. The step (D) comprises (i) placing quartz crucible contained with solid mixed fine powder in workbench of microwave radiation heating furnace; (ii) starting vacuum pump, pumping air in the furnace, and enabling vacuum degree in furnace to reach - 0.09 MPa; (iii) opening nitrogen valve, introducing nitrogen to furnace, controlling introducing speed of nitrogen to 200 cm3/minute, constantly enabling pressure in furnace to - 0.08MPa, closing nitrogen valve, and stopping introducing nitrogen; (iv) opening microwave ration heater, gradually heating furnace from 25 degrees C to 380 plus minus 2 degrees C, controlling temperature increment speed at 10 degrees C/minute, preserving heat for 10 plus minus 1 minute, and performing decomposition and combination reaction on solid mixed fine powder; (v) opening water circulation cooling pipe to execute external water circulation cooling while opening microwave radiation to heat; and (vi) performing decomposition and combination reaction on solid mixed fine powder at heating, constant temperature heat preservation, nitrogen protection and external water circulation cooling state. In step (E), the microwave radiation heater is closed so that solid mixed fine powder can naturally cool to 25 degrees C along with furnace under protection of N2 and under external water circulation cooling. The step (F) comprises closing external water circulation cooling pipe, stopping external water cooling, removing quartz crucible, and obtaining fine catalyst powder. Color, shape, component, chemical physical performance, and mechanical performance of prepared catalyst powder are detected, analyzed and characterized in step (G). In step (G), crystalline phase analysis is performed using ray powder diffractometer, and shape analysis is executed using scanning electron microscope, where conclusion is that catalyst is grayish-green powder and content of product active constitute nickel oxide is 19.67%, and diameter of particle is not more than 100 mm. The step (H) comprises tightly storing prepared grayish-green powder product in colorless transparent glass container, which is placed in a dry, cool and clean environment and should prevent water, sun, and acid-base salt corrosion. Storage temperature is 20 plus minus 2 degrees C, and relative humidity is not more than 10%.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating a method for preparation of catalyst for gas methanation of coke oven.    Microwave heating furnace (1)    Workbench (2)    Quartz crucible (4)    Cooling water tank (12)    Furnace chamber (22)