Abstract: The present invention provides a method for improving the stability of pramipexole or its salt preparation, and further provides a pramipexole hydrochloride oral liquid with excellent stability and oral absorption effect. The pramipexole hydrochloride oral liquid of the present invention is prepared through a simple process, and shows bioequivalence with the tablet containing pramipexole hydrochloride. The invention perfectly realizes multi-dose administration of pramipexole hydrochloride and improves the compliance and accessibility of medication for patients.