Abstract: In order to facilitate the technical implementation of GHS system in China, on the basis of the classification of new chemical substances hazardous to aquatic environment that have been registered in the period 2004-2012 by means of regular (normal) application, the methods for GHS classification of new chemical substances hazardous to aquatic environment were discussed. The application of GHS classification standards, the selection of data, the classification procedure, the identification of hazards and the statement of classification conclusions were elaborated, the classification methods of common but hard-to-test new chemical substances analyzed, and the technical problems relative to classification defined.