The invention discloses a radionuclide labeled benzopteridin derivative, and a preparation method and applications thereof. The molecular structure is disclosed in the invention. The radionuclide labeled benzopteridin derivative is used after cerebral apoplexy as quickly as possible, and diagnostic imaging is carried out 5min after drug using, and focus parts can be observed clearly, so that diagnosis time is shortened greatly, correct diagnosis is realized in the cerebral apoplexy salvage golden time, in-time guiding of effective treatment is realized, the best treatment effects are achieved,the risk is the lowest, and it is of major importance for patient disease prognosis.