The invention discloses a method for preparing tetraamminepalladium hydrogen carbonate, belonging to the technical field of chemical synthesis. The method comprises the following steps: (1) in a palladium tetramine sulfate solution, slowly adding an ammonia water solution of barium hydroxide so as to obtain a suspension with a great amount of precipitate BaSO4, wherein the mole ratio of palladiumtetramine sulfate to barium hydroxide is 1:(0.8-1.5), and the ammonia water concentration is greater than 1mol/L; (2) adding ammonia water of which a volume is same as that of the suspension and the concentration is greater than 1mol/L, and stirring to carry out a reaction; (3) adding sodium bicarbonate which is 2-4 times of the mole amount of the palladium tetramine sulfate, and continuously stirring to carry out the reaction for more than 2 hours; and (4) carrying out filtration separation, carrying out spinning evaporation on the filtrate, and crystallizing, thereby obtaining tetraamminepalladium hydrogen carbonate. The method disclosed by the invention is simple to operate, high in yield, high in product purity and applicable to on-scale production.