The invention provides a preparation method of a palladium-charcoal catalyst and further provides the palladium-charcoal catalyst prepared by using the preparation method and application of the palladium-charcoal catalyst. Compared with the prior art, palladium ions which are already adsorbed to a carrier are subjected to in-situ reduction through electrochemical in-situ reduction; compared with aconventional method that a reducing agent is added or electrochemical deposition is implemented, the preparation method is rapid in reduction speed, and the metal palladium takes the shape of sheetsand has a large contact area with the carrier, so that migration and dropping of the palladium metal can be well prevented, and the catalyst is high in stability, high in palladium atom utilization rate and good in catalysis performance; and meanwhile, a high conversion rate and yield can be achieved without adding other metals into the catalyst, and problems of separation and palladium metal recycling caused by conventional preparation methods can be solved.