The present invention relates to entecavir microspheres and a pharmaceutical composition for parenteral administration containing the same. The entecavir microspheres are manufactured by a method comprising the steps of: dissolving entecavir and a biodegradable biocompatible polymer in at least one solvent putting the solution of the entecavir and biodegradable biocompatible polymer in a hydrophilic polymer solution, followed by stirring, to form microspheres and removing the solvent. The entecavir is sufficiently sealed in the entecavir microsphere at approximately 80% or more based on the input amount, and the elution of the entecavir is maintained for 30 days or more, and thus the entecavir microspheres can continuously exhibit efficacy, thereby improving medication compliance of patients.
