The present invention relates to: a composition for dissolving thrombi comprising a peptide comprising the Arg-Gly-Asp motif; a pharmaceutical composition for treating stenotic or occlusive vascular diseases which comprises the same; and a thrombus dissolving method and a method for treating stenotic or occlusive vascular diseases, comprising the step of administering the same. The compositions and methods of the present invention have the advantage that they effectively break down already formed thrombi by adopting the principle of targeting integrin within the thrombus such as platelet surface GPIIb-IIIa, which is not the same as the existing principle of plasminogen activation. Also, the compositions and methods of the present invention have a nerve-protecting function as they effectively open as far as the microvasculature, without the occurrence of restenosis after penetration.