Cross-border discharge of nuclear contaminated water will cause irreversible damage to human health, the international Marine environment and even the entire biosphere. At present, the international treatment of crossborder discharge of nuclear contaminated water is faced with the following difficulties: first, the discharge standards of various countries are different, resulting in the inability to claim rights according to domestic standards; Second, the IAEA’s powers are limited and it lacks the power of decisive intervention, independent investigation and supervision. Third, the legal consequences of arbitrary emissions are absent. In this regard, the international community should strengthen cooperation and build a comprehensive system of prevention before the event, restriction during the event and relief after the event from the dual dimensions of law and technology.