The present invention relates to a method for preparing a granule or a pill containing a plant, medicinal herb or traditional oriental medicine decoction extract, having the steps of: (a) injecting a powdered plant, medicinal herb or traditional oriental medicine decoction extract into a fluidized-bed device and spraying purified water or a solution of the same type of extract as the extract powder at the extract powder while fluidizing the same, thereby generating microgranules of the extract powder and (b) injecting the microgranules generated at step (a) as seeds into the fluidized-bed device and spraying a solution of the extract while fluidizing the same, thereby growing the microgranules to a predetermined size of granule or pill. According to the present invention, it is possible to prepare a granule or a pill containing an extract in a high concentration.