A consultation and forecast diagnosis system of metal exposed in marine environment has been developed by using the object-oriented programming language,Visual Basic (VB).The system comprises three major modules:database and management system,corrosion prediction and corrosion morphology analysis.In the first part,the common data management function such as data input,data modify,data delete and data refresh are discussed.There are two different methods used in the corrosion prediction module,the artificial neural network (ANN) and gray model.Using the ANN method,the corrosion depth of new materials in different marine environment can be predicted.The gray model method can give the corrosion rate of materials in the future.The corrosion morphology images of metallic material in seawater,which are acquired by scanner,are stored in the database.Taking the gray distribution or fractal characters of metallic samples and their corrosion morphology as the knowledge base respectively,the diagnosing system identifying corrosion morphology of metallic material in seawater was established according to the theory of fuzzy pattern recognition.The corrosion morphology of sample can be identified by gray distribution or fractal characters of corrosion images.