The invention provides a catalyst for synthesizing trifluoroethylene and a preparation method thereof. The main active component of the catalyst is a mixture of single element Ni (nickel), NiF2 (nickel fluoride), AlF3 (aluminum fluoride), C (carbon) and additives M (Ce (cerium) and Pd (palladium)). The preparation method of the catalyst comprises the following steps of mixing an aluminum-containing compound, a nickel-containing compound and an M-containing compound, dissolving into water, and adding ammonia water until completely precipitating, so as to obtain a mixture of Al(OH)3 (aluminum hydroxide), Ni(OH)2 (nickel hydroxide) and M(OH)n; adding polyols into the mixture of Al(OH)3, Ni(OH)2 and M(OH)n, mixing, drying, and roasting under the inert atmosphere, so as to obtain a carbon-containing composite oxide; reducing the carbon-containing composite oxide by hydrogen-containing mixed gas, and treating by hydrogen fluoride-containing mixed gas, so as to obtain the catalyst. The prepared catalyst has the advantages that the activity is high, the service life is long, the anti-coking ability is strong, and the like; the catalyst is especially suitable for 1,1,1,2-tetrafluoroethane to remove hydrogen fluoride to synthesize the trifluoroethylene.