The present invention relates to a method for preparing clopidogrel 1,5-naphthalenedisulfonate or a hydrate thereof, which comprises reacting a clopidogrel-acid addition salt with disodium 1,5-naphthalenedisulfonate or its hydrate in water, or a mixture of water and an organic solvent. High quality clopidogrel 1,5-naphthalenedisulfonate can be prepared by the inventive method by way of using non-corrosive disodium 1,5-naphthalenedisulfonate.