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.