Marine environmental pollution incidents, which happened frequently in recent year, have done great damage to marine environment. It is of great significance to establish a sound early warning mechanism for effectively avoiding the occurrence of marine environmental pollution incidents or reducing their destructiveness. However, the present conditions, such as the weakness of the early warning principle and system related provisions that embedded in legal documents, the difficulty of early warning coordination resulted from the classification system of marine environment management, the deficient information system arising from monitoring technology, facilities construction, and information sharing, affect the effectiveness of early warning management. Based on the experiences of the foreign countries in marine environmental early warning, policy recommendations can be provided as follows: Early warning principles and systems should be fully embedded in legal documents of marine environmental protection; The comprehensive coordination mechanism of early warning should be improved; An efficient application platform of early warning system for marine environment should be constructed.